"Other games did X" really isn't a valid argument. You made an error, but you want to blame it on someone else. I don't see that this is going to get resolved in your favor. Sorry.
While I agree saying what other games do is worthless however he may still be in the right as the description within the cartel market states subscribers don't need it in the blue text while all other items (that I know of) state that very same thing within the yellow text. So frankly he did lose his coins due to BW inability to remain consistent. However because it does still state it I doubt you will get a refund, but I could be wrong.