Card Decline Errors Block Vodafone's Free 3-Month ChatGPT Offer

While trying to activate the 3-month ChatGPT usage benefit I earned through my Vodafone line, I keep getting a "card declined" error during the credit card and debit card verification step. I'm running into the same problem with both my credit card and my debit card, and because of this, I can't use the benefit I earned.
I have a postpaid Vodafone line, and I started getting this error today. I hadn't experienced this kind of problem before. Even though there's nothing missing or mismatched with my cards or my information, the system won't accept the cards and the process can't be completed.
I'm requesting that my situation be resolved, that the necessary checks be carried out so I can use the 3-month ChatGPT benefit I earned without any issues, and that this problem be fixed urgently. I specifically want to note that I'd like Vodafone to get back to me as soon as possible and keep me informed on this matter. My GSM number for reaching me is: 0530********54.