Android Question

Why is my mobile data not working on my Samsung Infuse? I have ATT service. It has worked the whole time I've had it, but now my data icon is gone and I cannot get it back, no matter what I try. I even went and got an updated SIM card because mine was 7 years old. I have tried checking APN settings, verifying "use packet data" was active, etc. but nothing has worked. Also, the liquid damage indicator is still white, so it shouldn't have any water damage. Any other ideas as to what might be wrong, please?