Sony Expeira \Sudden Death\""

I recently bought a Sony Experia M5 from MTN Burgersfort. The phone was little over a month old when it suddenly started to shut down for no reason. Then it cannot be restarted unless I connect the battery. I went to my MTN store and they informed me that they received an email from Sony informing them to stop selling the M5 immediately as they are experiencing problems with the devise. MTN told me they cannot help me as I didn't keep the box. I phoned Sony mobile SA hoping they would be able to help me. Even though they are aware of the problems this devise gives, they refuse to help me. I think it is very poor customer service. I sit with a brand new phone but because I did not keep the box, no one wants to help me. I will never ever buy any Sony product again. And I will warn everyone against Sony products. Looks like samsung is the better choice no a days.