[Resolved]  Nokia 2112 — Signal fades and never comes back

I have a Nokia 2112 on the Reliance CDMA network. I accidentally dropped it in a bad manner and then got the display changed at Nokia service Centre in out of warranty situation. but another problem has crept in. now the phone recepts signals only for the first two minutes after being swicthed on. Thereafter the signal fades and the phone will never catch signal until switched off & then on. again the problem repeats itself. No Nokia priority is able to give a satisfactory explanation for this absurd behaviour of the handset.