Cell phones: Cingular is Cancelling Our Contract...?!?

Cingular is Cancelling Our Contract...?!?

This is the situation: My husband & I live in Pittsburgh and have a 2-year contract with Cingular which was due to end this summer. Hubby's 18 year-old son lives in Minnesota, and last summer, we added him to our Cingular Family Plan and bought him a Motoroloa SLVR L7. It was a strange arrangement in that his cell phone has a Pittsburgh area code even though he's using it in Minnesota. Everything seemed to be working well until I received a letter from Cingular stating that we had violated the terms & conditions of our contract and that as of April 1, 2007, they were cancelling our contract. I called Cingular & they stated that in the rural area in which my stepson lives, there are few Cingular towers, and his phone is actually having to use (at Cingular's expense) other carriers' towers. They "graciously" allowed us out of our contract period as of April 1 with no penalties. They are also providing us with the Unlock Code for his phone so that it can be used by another carrier.

Now, stepson is coming to live with us in July. We will need to go with a new carrier here in Pittsburgh and provide service for him in Minnesota until July.

QUESTION: After his phone is unlocked, is there any way to sign him up with a pre-paid service with his SLVR for the months before he moves here? We will then have to add him to our Pittsburgh service.

Or is there a simpler way to do this???

Sorry for the convoluted details... life is never simple anymore!

Thanks for any advice.