why won't my sim card work?

[rickportega]

I purchased a 7100g off ebay, and under the "network" section under options, it says cingular, whether my sim card is in or not. When I put my active sim card in, it says "invalid sim card". The phone is locked, but I thought since it says cingular under the network section, my cingular card would work. Anyone know what is wrong? The sim card works in a different cingular phone, so its not broken. Should I get the phone unlocked?

[d_fisher]

Do you have a BlackBerry data plan?

[rickportega]

no, just phone plan w/ text messages. Even without a blackberry data plan, I should be able to make calls, right?

Also, I forgot to add in my orignal post. The seller of the phone told me it was on the tmobile network, so Im not sure why it says cingular on there. Is this even possible if it was previously on the tmobile network without being unlocked, or is the seller mistaken?

[d_fisher]

You will need to get the device unlocked to work with AT&T.

[Dubdub]

If the phone is a Cingular phone, it shoudl work with your ATT SIM. If it is a T-Mo phone then it would need to be unlocked to work with your ATT SIM.

Also, since you bought it on eBay, you really can't be sure that it hasn't been reported as lost or stolen or that the seller did not have an up to date account. That could also be the problem.

Have you tried to contact the seller? That should be your next step - and try to get your money back.