Missing Repair Phone

Extremely disappointed in the service recieved from MTN Store Groblersdal Mall. I booked a phone in for repairs almost two months in the store, now the phone is missing and unaccounted for. They keep saying that they are logging tickets but those tickets are not being resolved. The phone was picked up but till today there's no quotation or any sort of communication from the store and yet am paying my montly subscription for a phone that I am not using and currently in the possession of the service provider. No follow up is done until I pay the store a visit. The store phone is NEVER EVER answered. How do I continue paying for a phone that went missing? Either replace the phone or cancel my contract cause what's the point? The phone is gone and am being given the run around.