Not receiving assitance from 3 different bracnches

I am a loyal MTN customer and have always only used their products. I received a call from one of their agents selling S4 Samsung cellphone telephonically and it was agreed the phone will be delivered to my work place. As promised I received my cellphone and signed a paper of receipts of goods and nothing else.<br> <br> Unfortunately my S4 Samsung fell and I could no longer use it as the screen/LCD was damaged, I then visited Samsung as the is an offer to fix Samsung screen phones but proof of purchase is required for this and I have been struggling to get a proof of purchase from any MTN store as they do not have it on system.<br> <br> Its quite disappointing, I feel no one is willing to assist as long I really am asking for is my proof of purchase of the item I have been paying for and need to fix so I can use it.<br> <br> At this stage I am exhausted and have tried to ask for assistance so many times I don't know who to contact.