Reward Card - Lost/Found

I have been a loyal AT&T customer for a long time, until we moved to a city that does not offer Uverse in 2018. I have attempted to speak with someone about a reward card that was mailed to our previous address, forwarded, lost and finally appeared. It’s several years old, but help me understand why my loyalty was met with “you need to call your bank” ( What?!?! It’s a reward card YOU issued?!?!) So, basically, “too bad, so sad?” I still have my AT&T wireless and NO I don’t want this credited to my wireless bill. I earned the reward and should be able to spend it however I choose.