I don’t know much about the main store unfortunately, I haven’t bought off it in years, although I plan to soon, but that’s not really going to help now. Only other thing I could think of is to make sure O’s and 0’s (and other similar letters and numbers) aren’t switched or something, I can’t remember what the codes looked like
Hopefully they fix the problem soon
Edit: The picture of the main store discount card seems to say it’s only select items. Not sure what that means, unless it’s stated on each item on the store that discounts can be applied to or not