In June this year, I tried to buy fuel at a Super U fuel station at Andard in the Loire valley near Angers, I inserted my Starling card ( which I have used many times in France) and entered my pin number, the system checked with my card issuer and then declined the transaction, I requested a receipt even though the transaction was for zero euros. I didn't know why the transaction was declined so I tried again with the same card ( I had 358.67 euros credit and about 1000 sterling on the card) , the same thing happened I got another receipt for zero euros. I tried my Mastercard credit card, it was also declined, I then tried my Ulster Bank debit card, it was also declined. I thought the system must be faulty and left the service station. Later that day when I checked my Starling account, I discovered that Super U had requested a prepayment of 500 euros from my account. As my account only contained 358.67 euros it took the full 358.67 euros from my account leaving me with no funds in that account, I would have expected that if the transaction amount was zero, then that's what I would have been charged. I contacted Starling and they told me that when the transaction changes from pending, they will contact Super U. The transaction didn't change from pending, I contacted Starling a few times, and I think, because of the odd amount, they didn't believe I didn't get any fuel. I was able to forward copies of the zero receipts to them and eventually after a couple of weeks, they refunded my account. Now, when I use these unattended fuel stations, I always get a receipt and keep them until I see that the correct amount has been deducted from my account. I still can't figure out why they requested 500 euros, most other stations I have used, request about 100 euros and limit the max fuel you can take to that amount. I sent emails to customer services at Super U, but I still haven't received a response from them. My fuel tank only holds 100 litres which would be a maximum transaction of less than 200 euros. I have no problems with that card at any other service operators. Beware.