did you have insurance on your Pearl? You may just have to get it replaced
Also, I had problems with my pearl when I first bought it. The lil threads in the charger port kept acting up and it wouldn't charge and I had to have my Pearl replaced twice in about 4 months and T-mobile was kind enough to replace both of them and all I had to pay for was the shipping to have the new one sent (it was like 20 dollars for UPS to ship it and they just add it on your bill)
oh did I mention that I don't have insurance on my blackberry? guess that might give ya a lil more insight into t-mobile. they are usually really good about working with you to get what you need. they didn't make me buy a new phone or anything when I had my issues