How to restore iTunes credit card payment

Thank you very much for your kind advice. I’ve done that twice from the settings on iPhone. Is there a way of contacting iTunes directly? Or what should I do if this perseveres. My bank advised inserting details of another card issued by them. Very unlikely solution. There must be something more to it. Only people dealing with cards iin Apple could explain.

FYI had to use iTunes pre paid vouchers but for that needed to delete my Visa card from fine, then put a new address which had to match with currency of vouchers - they had only 2 in the local bookstore & sold me dollars which could not be used with local address ... so had to exchange coupons, then my SIM card died for some obscure reason, so had to buy a new one. This enabled me to receive codes for logging out of my current Apple ID and setting up a new one with a new mail address and password ... was very lucky as got out of work at 17H and stores here close at 23H... managed it thanks to very kind bookstore staff in 5 hours... so if you have a bank account in one country, permanent address in another and work in a third ... buy iTune vouchers, they come in 100-200 dollars where I work... that’s the easy part ...