Here’s what happens: When you thought the scammer deposited money in your account, it didn’t really happen.
It was essentially fake money.
This could happen in a few different ways.
It could be that the scammer gave you a bad/fake check, which isn’t discovered until several days after you deposited it.
Banks don’t know for sure if checks are good until they send it on to the issuing bank.
As a courtesy, your bank will assume it is good as soon as you deposit it and credit your account immediately, but if the check turns out to be bad, they will withdraw that amount back from your account, and if you have already spent that money, the bank will want you to pay it back.
There is also an electronic version of this scenario: If you are electronically sent money from an account by mistake or an account that was hacked, this can be reversed.
On the other side of the scam, when you send money out of your account to the scammer, you are doing so willingly, even if you were tricked into doing so.
You went to the bank and withdrew the cash, or you wrote the check, or you initiated the electronic transfer out.
Your account was not hijacked; you told the bank what you wanted to do with your account.
You can’t normally just change your mind after the fact.
If the scammer took control of your account electronically and stole the money, or the scammer forged a check without your knowledge, you would generally be able to get your money back from the bank.
But if you willingly hand money over to the scammer, you will need to go after the scammer to get your money back.
money.stackexchange.com/users/10997/Ben Miller - Remember Monica
Some payment methods people are able to cancel or the money doesn't fully exist until 'cleared', some not.
This scam works by sending you money via one that can such as a check, followed by you sending them money back via one that can't , typically Western Union, cash in person or via crypto etc.
They then cancel the money you got, leaving you out of pocket and with no way to cancel the money you gave away.
money.stackexchange.com/users/32392/Philip
How do scammers [do something...], while you can’t?
A major factor here is the willingness to commit a crime, particularly fraud.
For example, you can reverse a credit card charge by calling the customer service number and complaining that a purchase was unauthorized or fraudulent.
Normal people do not lie about this because there are real consequences.
In fact almost all bank based consumer electronic transfers can be reversed long after the fact in case of fraud.
Some electronic transfers like Western Union or Bitcoin can NEVER be reversed.
Withdrawing the money as cash is another non-reversible action.
Paying money from a reversible transaction using a never reversible one is a common theme in scams.
Many fraud schemes are based on transactions where a bank will show money in a consumer's account before the bank actually receives the funds from the transfer.
This is sort of a loan.
Checks from another bank, for example, take several days to clear .
If the check is fake, the other bank will not honor it and the consumer's bank will take back the money they loaned.
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Sometimes the scammer doesn't even need to intentionally cancel the original payment.
They might send you a check, which you deposit in your account.
Your bank accepts the check and it may even post to your account because the bank assumes that it is legitimate (and it does appear that way at first).
A couple days
/weeks later the bank finds out that the account tied to the check does not exist or doesn't have any money in it, and they reverse the deposit.
Other times, the scammer requires you (the scammee?) to send them payment via a non-reversible method, like Philip stated .
money.stackexchange.com/users/71269/Nosjack
The only entity who can revert done money transfer is the bank itself, and they will do it only if there was something very wrong with the transfer itself, for example transfer resulted from system failure or the money came from criminal activity (from the account, that was closed by the law enforcement).
However, if you send the money from your bank account that is not blacklisted and contains legitimate money, so there's no reason to cancel that transfer.
Well, if your account was used to wash money, it might be blacklisted then, but you'd loose your money anyway, and the money sent to another account was most likely taken out.
Notice that it's a money washing schema.
Criminals can't revert done money transfer on their own, and they have no interest in having their accounts confiscated by the police, so reverting the transfer is only a side effect (and most likely, only the beginning of your transfer).
money.stackexchange.com/users/83612/9ilsdx 9rvj 0lo
I see a lot of question about scams with the same premises:    Someone puts money in your account.  You send money somewhere.  They take their money back, while you lost your money.   I don't know a whole lot about banking and money transfers, but it seems odd to me that they can retract money back while you can't do that.  Can someone explain this?
How do scammers retract money, while you can’t?
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money.stackexchange.com/questions/107003
money.stackexchange.com/users/83829/darnok
With some payment methods it is possible to cancel. There are transactions that show up before the money has actually cleared. If a scammer took control of your account electronically and stole the money, you would usually be able to get your money back from the bank. Some payment methods enable you to cancel or the money doesn't fully exist until it is  'cleared'. Paying money from a reversible transaction using a non-reversible one is a common theme in scams with many fraud schemes being based on transactions where a bank shows money in an account before it actually receives the funds from the transfer.
If a scammer took control of your account electronically and stole the money, you would usually be able to get your money back from the bank. Some payment methods enable you to cancel or the money doesn't fully exist until it is  'cleared'. Paying money from a reversible transaction using a non-reversible one is a common theme in scams with many fraud schemes being based on transactions where a bank shows money in an account before it actually receives the funds from the transfer.