Nokia — no signal

I had given my phone for repairing to HCL NOKIA CARE(A-78 sector -2 noida) on dated[protected]job sheet no [protected])with the problem of NO NETWORK and they told me that they will send it to Banglore for repairing and i received my phone on 15-10-08 but after two days problem comes again NO NETWORK. then i had contect again to HCL but they told me that this office is closed now you may contact MICRONAS TELECOM(C-4 sector-2 noida). I had again given my phone to microns telecom for same problem on 17-10-08 then they told me that they will send it to Banglore for repairing and i received my phone on 15-11-08 but next day problem remain same then again i have submit this phone to micronas telecom on 18-11-08 my job sheet no is[protected]/081118/105
Today i have visited MICRONAS TELECOM to collect my phone then they are saying this phone is tampered and you had repaired it outside now we can't repair this phone.This is to inform you this phone is under WARRANTY so no need to be checked out side.so pl change my phone immidately.