I am familiar with many cases where credit card bills with purportedly the correct address on them are never delivered or mailed late. It is not beyond the realm of possibility for a credit card company to correct an address after non-delivery and generate new "copies" of old bills with the now correct address.

Failure to receive a bill on time (or at all) is a violation of the Fair Credit Billing Act. Notify card company is writing within sixty days of time you become aware of problem using special billing error address. Have proof of delivery of your billing error letter (Certified Mail, Return Receipt Requested). Telephone calls do not protect you under the Act.

By the way, if the card is issued by a merchant and the problem transactions are with the merchant you may have broader protections.