Nokia / Nokia 2630 — Hanging issue in new mobile device

I bought NOKIA 2630 as on Feb 17, 2008 from "The Mobile Store". The same day I started facing hanging problem. I went to NOKIA care after two days and they replaced the software, but that also didn't resolve the issue. Then NOKIA asked me to deposite the device in service center and I did the same. I got the same on Mar 3, 2008 almost after ten days, but still the problem is there. They are again asking me to deposite the device. They are not agreeing to issue new device with difference money. Please look into this issue.