Nokia Care — Phone hanged

Address:

New Delhi, Delhi

I purchased lumia 520 14 months before, recently i have faced the same problem like many user are, suddenly it stop working and showing the error "unable to find the boot-able option press any key to shutdown ", i went to okhla ph|| care center, as happened with other same happened with me they said, "problem is in motherboard it will replaced and it cost around 40000-/ rs ", and before checking the said that it may become dead during the check, i said ok just do the check, later on i came to know from my friend who is mobile hardware engineer that they had changed my phone's mother board with the faulty one, why cell becomes dead beacuse they have given 12 volt supply so that nobody can track the motherborad is related to this set only .Because this becomes dead .Please do some need full, please give the replacement option or reimbursement to me.