My cafe Nero code coming up as redeemed

[Wonder]

I usually download £1 cafe Nero code from three plus on a Monday and use it at cafe Nero when I go. Today and a couple of previous times the code has come up at the shop as having already been used when in actual fact it hasn’t. So I’m then having to pay the full amount for my drink rather than the £1

[Digger]

Same here. Don’t get why it doesn’t work once you’ve claimed it. You just get blank looks in Nero. I just leave the coffee on the counter.