If you see a suitable moment you might remind them of a commercial truism that a previous boss of mine had on his wall:
"The customer is not always right, but there is no profit in proving him wrong."
Wex's rep has been rather good, and I would have thought of them - but I am reconsidering now, and I may not be the only one.... how many orders do they want to let slip?
This line in the reply I finally had from them this afternoon caused me no little concern;
'I have forwarded your emails to our call centre manager for further advice on this and his instructions on how he would like us to proceed'
I didn't think when I got in touch with them by email regarding a technical issue that I'd be dealing with a call centre.