The first time Susan Vasey knew of a £10,000 loan in her name was when police arrested her, she told a jury at Worcester Crown Court.
On hearing the recorded call she recognised the caller as her ex.
Matthew Samuels, of St Johns, Worcester denies 11 counts of fraud.
The 50-year-old, of Broadway Grove, is accused of tricking five women and his own stepson out of about £180,000.
Divorced Miss Vasey met Mr Samuels on dating site MatchAffinity.com when he was living in Staffordshire.
She told the jury he helped her get a finance deal on a Vauxhall Corsa through a car dealership he worked with.
But she claimed that, in early 2013, Mr Samuels told her the remaining £6,000 on the hire purchase agreement was due immediately.
Miss Vasey said she went to her bank and arranged a loan to buy the car outright but handed the money to Mr Samuels, who was to make the payment.
She claimed that in September last year she discovered paperwork showing the car had never been paid for and about £4,000 was outstanding on the original hire purchase deal.
She said: "I didn't know what had happened to the £6,000, I only knew it hadn't been used to settle the finance on the car."
The trial of Mr Samuels continues.
A man accused of a £180,000 online dating scam feigned laryngitis over the phone to dupe a bank into giving him a loan in his girlfriend's name, a court has heard.