MANUFACTURER J5 DEFECT

I upgraded my contract on the 18th January but the 1st day I used the handset it froze for over 14hrs until it exhausted the battery, I charged it and it was fine the next day. It did the same thing several times even though most times I didn’t go to the store and I eventually took it to MTN Dainfern, they booked it for repairs three times (I do not have 2 dates on record, I then called MTN SERVICES while in the store to cancel my contract and I was told I am liable for payment for the remainder of the contract since the handset has factory defects, they (MTN SERVICES) advised that the shop is responsible for the defect and they should replace the handset but the shop refused. I then accepted they book it in for repairs. On the 21st July it was the same problem, I went and spoke to the sales man who referred me to the owner of the store, the owner (Suvan Maharaj) promised to replace the handset as soon as he can get the reference number from their repairs department, I was requested to bring back everything including the box I got with the handset which i did and someone will contact me to come and take another handset but nobody contacted me. On the 25th July I went to the store to and I was told my phone was booked for repairs and I can only get it back on the 28th July. The salesman I was dealing with was not present at that time. On the 26th July I called Suvan Maharaj (SHOP OWNER) on his mobile and he promised me to replace my handset. I am afraid I’m every month for a handset that has defects from the manufacturer and I am the one who is losing money over this contract since it still hasn’t been replaced .I have not found joy in using the handset because most of the time is hanging, as a result I have lost a lot of information on the handset due to it being sent for repairs.