Oh that happened to me with the printed cadburys coupons (I think Sam might have put them up too!)
I printed a few off (it didnt give a limit!!) and took them to tesco. Got the dumbest assistant ever who took forever to understand what I was trying to say and then finally told me it was only for dairy milk original so for the third time i had to read her the wording ON the coupon that said it was any type (caramel etc) she called a supervisor and I wished i hadnt bothered! (got a bit determined in the end though, it was a REAL coupon!!)
Milly's mum, I got a troubleshooter thing when it didnt work - it asked me questions (have i printed it before, etc) and when I said no, etc it asked if I wanted to apply to have it by post - got the form up.
My lot love Felix but it makes them very.... let just say gassy! LOL
Edit I pressed submit and its told me I already had one...