Bad frustrating experience

MTN Service provider is unable to help me to repair my newly upgraded Sony handset,i upgraded on the 31st of Dec 2018, it is still under warranty, the handset does not charge it just went off, i handed it over at Wonderboom Junction Mall outlet on the 25th of Jan 2019. One of the consultant called me on the 08th of February 2019, he told me that the company instructed them to call me, to come and take the handset and make direct contact with Sony for repair, this information was never disclosed to me when i bought the handset . i did send email to MTN CUSTOMER SERVICE till this day thry have never, responded to my quiery or even called me for that matter. They are busy deducting full contract amount from my bank