PHONE NOT BOOKED IN!

I have honestly had it with MTN and **** service. I am at a point where I want to settle the contract I have with you and never associate myself with this network ever again. In September of 2017 I took out a contract with MTN, received the phone, but had a week long struggle with changing my prepaid number over to the contract. Twoo weeks later I got the phone working and was happy but thought I wanted to take out insurance on the handset but was sent from pillar to post with getting insurance on the handset. Fast forward to April 2018 the phone's speaker/microphone started giving me problems. I went into your Cresta store on the 04/04/2018 and my phone was booked in by a lady called Nomkhosi Mavuso and was told that I would get it back withing 2 to 3 weeks. Today being the 17/04/2018 I decided to give that After Sales Contact Centre ( ********** 349) a call and was told they cannot find anything under the IMEI number or the my cellphone number. For almost a week I've been without a phone and it looks like my phone hasn't been booked in to your repair centre! I tried to call the Cresta store where I initially left the phone but the phone goes unanswered. Am i supposed to go a month without a phone that I am paying for???????????????? I am really fedup with MTN. Can someone tell me where my phone is and when I'm getting it back.