"We're in a difficult position," she says. "My partner's very unwell. We are a family business, a small business. Literally everything we make in the shop, we haven't been paid for until someone buys it. So, it has a big impact when someone steals something."
"We make everything from scratch. We make all our own gold alloys, in 28 different colours - grey, gold, green-gold, peach."
Despite her high-value goods, Ms Day is reluctant to lock her door to customers.
"I really want it to be welcoming. I don't want to be a 'buzz people in' kind of jewellery shop," she says. "I just think it stops people coming in to look."
In the summer months, tourists come to Dartmouth. This is when Ms Day's shop is at its busiest.
"They don't come in to spend money," she says. "They come in to have a look around, and then they're like 'oh, this is so pretty!', and they accidentally spend some money. I don't think those people would come in at all if you had to buzz in."
Ms Day keeps her products in cabinets and in the window, with a few items out for people to pick up. Following the first theft, however, they had an alarm system fitted, with a panic button that immediately alerts a security company and the police, and cameras with signs up on the walls to say they have CCTV.
"We also put a really ringy bell on the door!" She adds.
But the best piece of tech they have invested in, she says, is a simple doorbell style camera that sits on the counter.
"It's really high quality footage and records the whole shop," she says.
Following the most recent theft of a necklace worth Â£685, the police identified the thief using footage from the doorbell camera - and made an arrest.
In the year to June 2023,the police recorded a 25% increasein shoplifting in England and Wales, and across the UKretail theft costs an estimated Â£953m- despite over Â£700m in crime prevention spending by retailers.
Meanwhile, in the USretail crime cost the industrymore than $112bn (Â£92bn) in 2022 - losses which push up retailers' operating costs and consequently increase prices for customers.
Retailers are taking all sorts of measures to deter shoplifters, includingfunding a police surveillance project,hiring undercover guardsto patrol shop floors and evenoffering free coffees to police officersto tempt them into their stores.
"We've heard examples of businesses using facial recognition to prevent retail crimes," says Tina McKenzie, Policy Chair of the Federation of Small Businesses (FSB), "but to many independent shop owners, this may seem like a luxury item - especially with soaring inflation and high interest rates."
Small businesses often find themselves in the cross-hairs of business crime, she says, and usually these crimes take "a backseat to other forms of criminal activity".
"Many choose not to report to the police because they're not confident that the criminals will be found and successfully prosecuted," she says. "In the long-run, this hurts the wider economy.
"A stable and safe environment is necessary for small firms to flourish. We'd like to see organised shoplifting and antisocial behaviour taken more seriously, so that High Street staff and customers feel safe on a day-to-day basis."
A recent Co-op led reporton retail crime found authorities failed to respond in more than 70% of serious retail crimes reported.
According to the study,criminals have "freedom to loot"in a situation that is "out-of-control".
"[The criminals] are not worried about consequence. They're not worried about any response or prosecution," says Steven Logue, the Co-op's head of operations.
This lack of repercussions, says Mr Logue, is likely the catalyst for what has been a "staggering" rise in thefts over the past year.
"We have a stock loss of about Â£80m a year," he says, "but we are only reporting a fraction of what has been stolen. The unpalatable truth is that the response really hasn't been good enough in the last few years. So, these numbers are just the tip of the iceberg."
This year, the Co-op has already recorded a quarter of a million claims, with a thousand physical assaults, says Mr Logue. This is not a victimless crime.
"We see our colleagues trapped within kiosks, while [criminals] help themselves to cigarettes and alcohol," says Mr Logue. "These are people's mothers, daughters, brothers."
More technology of business
In October,the Home Office announcedthat shoplifting will be treated like organised crime as part of a plan to help police to crack down on theft.
"There are encouraging noises now being made by the police and Downing Street," says Mr Logue. "This is the first time the narrative is beginning to change."
To deter shoplifting, the Co-op has invested in "risers" at the front of shelves, which make it hard to reach the products, CCTV, remote monitoring, panic buttons, Smartwater, GPS-tracked security cases, body-cams and communication headsets, and covert security guards. They are now looking into installing secure kiosks and digital doors, so customers can't access high-value products without a member of staff unlocking them.
The Co-op has also been trialling empty dummy display packaging for higher value products such as coffee, chocolates and washing powder. Shoppers pick up the dummy display case which is exchanged at the checkout for the actual product.
However, Mr Logue says dummy packaging can be detrimental to sales.
"Our insights tell us it puts the customer off as much as it deters the thief, who just goes to another part of the store," he says.
There isn't one solution, says Mr Logue. "I think going back to old-school, physical guarding is best for preventing the more impulsive theft - but this is less effective for habitual repeat offenders."
In the past few years, the Co-op has in total invested more than Â£200m to counter criminal behaviour.
In the future, Mr Logue believes AI will have an important role in preventing retail crime.
"We are really keen to see how AI might be able to monitor people not scanning through the self-service kiosks, or the concealment of products in the aisles. It might allow us to react quicker in the moment, to trigger a call to the police."
Back in Dartmouth, the shoplifter who stole from Ms Day's shop has been given a suspended sentence.
"[The offender] had a gambling problem, it turned out," she says. "I feel sorry for him. I'm pleased the police managed to catch him - but I don't feel overjoyed about it. I don't feel like it was a good outcome for anyone really.
"I just feel sad about the whole thing really. I wish we lived in a society where I could have my door open, and people could just come and see our beautiful things - and I didn't have to panic about people coming in and stealing from us."
Isabella Day founded her jewellery shop, The Remarkable Goldsmiths, in Dartmouth just two years ago. Since then they've had around Â£3,000 worth of goods stolen.