"No service" from mtn

My contracted expired on 19 february 2018....i sent an email and called mtn to cancel my contract 1 month before expiry date....reason being the shoddy service i got from mtn pavilion when i walked in to upgrade.

Khethiwe.Makhanya called me from the retention and winback department and was very apologetic regarding the bad service i received. She worked out a deal with the P10 lite to my satisfaction, and discussed a credit as soon as i upgrade. For the past 3 months, i have sent emails, called mtn, nobody seems to know what is goin on. I went into the store, they adviced that i called the person i spoke to. I cannot get hold of Khethiwe.Makhanya....i have emails from her.....why is mtn not responding, when i cancelled they called me within minutes after me sending my cancellation letter....it is over going on the forth month, no reply from mtn