To want to swear at a rude man in a BP petrol station 😡😡

Near me is a BP petrol station with M&S food, is a bit pricey but this morning I needed a few bits and couldn’t be bothered walking to Lidl after a bad night with my DH.
There is a self service screen I always use, and doing nobody there I went to put my items through but was suddenly pushed aside by a man who told me I would have to cancel my shopping because he had put his diesel on there. No sorry. Nothing. Obviously he had put his diesel on there but instead of paying for it had then gone to do a bit of shopping as well which he had in his hand.
A very nice member of staff cancelled my shopping so that he could pay for his diesel and his items. She then apologised for the man and put my shopping through by hand. And a woman in the queue called the man a rather choice name but he had left before all this.
I would have liked to say something choice to him myself but was taken by surprise and would probably have only got a mouthful of F words.