SHYTOT:
similar amount to us, might be time to use someone else’s card for a week or two
Thats what I do if they dont play ball, I get all mine to brim their tanks over the weekend and then use a rival card for the next fill, which normally takes us upto about wednesday afternoon / evening…
Just about right to start the alarm bells ring @ Crewe HQ…boom, the price drops or its a game of Russian roulette 
You just need to be able to stand the pain of the rival card [■■■■■ terms / price / customer relations] for the rest of the week if they decide to leave you out to dry 