Unfortunately, prepaid phone cards are not eligible for exchange. However since you mentioned that there's no expiry date, you should still be able to use the ones you currently have. We apologize for any inconvenience. Thanks for reaching out.
Darais, AT&T Community Specialist
Need help? Ask a question to get help from the AT&T Community or support from AT&T specialists. If this reply helped you please use Accept solution to mark it as an Accepted Solution.
*I am an AT&T employee, and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.