which they wrote on their form before entering on the computer as they have written then who's fault is it if the customer complains it has been paid into the wrong account or under the wrong name?
If the Customer wrote it down wrong then it's their fault.
If the customer wrote it down correctly and you typed it in wrong then it is your fault.
But if they were paying into an account at the bank you worked for, wouldn't you check that the account holder's name and the account details given match up?
At a guess it was the customers ,it was them who gave the account number ,