5 times repaired till not fixed and redirected

My Galaxy Note 4 has been in repairs at MTN 5 times and it's still not fixed they said they will not work on my phone anymore and made an excuse that the lifting screen was for expansion but the lifting screen causes the return button not to function. The manager at MTN repair centre port elizabeth said he is tired of my phone having spent so much money on it and redirected me to complain here at hellopeter. I am furious that I am paying MTN for this device but I am unable to use it, I have been made aware by Samsung that the device should have been replaced already but it has not been replaced. Could someone from MTN please contact me. The phone has been in repairs for a month now and as MTN repair centre said they won't be repairing my Galaxy Note 4 again.