faulty new phone

I upgraded my Cell c contract in August 2015. I received the Samsung S6. Two weeks later the phone started going faulty. Whenever it was charged it was getting very hot and would cut out. However the matter was not reported immediately as the device continued to work intermittently. On the 14th October i lodged a repair complaint at Cell C direct. The phone was collected on 21st. I then received an sms on 2nd Nov stating that the quote for repair is R4101.74. I phoned to query what was wrong with the phone.( ref CLC***) I was informed by the technician that the main pc board and another one had corroded. I queried what could have caused this as the contract was less than 2 months old. He advised he did not know. I specifically asked if it was water damage and he stated no. I requested the suprvisor to phone me. She called and stated that the device had in fact been water damaged, contrary to what the tech had stated. I have never dropped the phone in water or allowed it to come into any contact with liquids whatsoever. It is a brand new device that has given problems since it was received by myself. I wish the phone to be replaced at no charge to myself whatsoever.