Purchased XBOX Live Card, called for tech supt who said it isn't compatible w/Wireless Internet w ATT Uverse?

Can someone confirm this true or did I get an off answer? Thanks. I do have ATT Uverse cable w/tower but tech said still NO compatibility.|||You may have to go into the Att router control panel and tweak settings but we have no problem using ATT for xbox live.|||Any Xbox Live Code will work no matter how you are connected to Live. you got a wrong answer.