The supermarket has recently hiked the pre-authorisation charge at its pay-at-pump service from £1 to £100, affecting any driver who fills up at one of its pumps.
The money never leaves your account but is ringfenced and appears as a pending charge on statements, meaning you cannot spend it.
The funds are usually released within 48 hours but a number of drivers have reported being caught out by the charges and left short of funds for other purchases.
One shopper found that she was pushed into her overdraft by the pre-authorisation charge despite having enough money to cover the £30 cost of her fuel.
Others have reported having to wait several days for the funds to be released, with one commenting: “I had this too in Redditch and visited the store three times and it’s still not back in my account five days later."
Another added: “I didn’t realise as it was usually £1 there but I left the garage - £100 plus the cost of my petrol.... I know they will refund in 48 hours but still.... that was not expected."
Morrisons is the latest supermarket chain to introduce the higher charges, following Tesco and Sainsbury’s, which did so last year.
The change has been forced by credit card companies Visa and Mastercard and comes despite a huge backlash when Asda trialled the charge at its pay-at-pump sites in 2018.
Morrisons said the change was introduced in November 2021 and advised any drivers who wanted to avoid the £100 pre-authorisation charge to pay inside the petrol station rather than at the pump.
Aex Neill, CEO of financial advice service Resolver previously urged customers to flag the non-refund as soon as possible.
He told the Sun: "If you find that the charge has not been released or refunded after a day or two contact your bank or credit card provider immediately, explaining what has happened.
"You should get an immediate reversal of the funds."