What can I do about the OS on my T300 crashing?

This has happened and I lost all my data(phone numbers, appointments, apps), and for some reason the hot-sync wont work. so now im looking into upgrading to the 600, but some problems arise:

1) I've already used Sprints replacement plan
2) Since I used that, I cant return phone to the store I bought it at(different s/n)
3) Palm1 isn't helping at all.

any guys got any ideas on how to upgrade? I cant really afford to pay $600 right now for a new one.