Issues with gift codes

Has anyone ever had issues redeeming gift codes? I sent out a mass message with a new code and I had a member tell me they can't redeem gift codes as after they do so they can't buy in game packs and has to get with Apple support to fix it each time. I tried to use their ID to redeem the codes on the community site https://wosrewards.com/ but the gifts didn't go anywhere I'm just wondering if anyone else has had this issue or if there is a way to fix it for them