Threatening to disconnect me even though i paid

Mtn will continue to disappoint. I have made a payment on the 26th Feb via there mtn app. They are sending me threatening messages saying that they going to disconnect my number should i not make a payment. I have sent them numerous times proof of payment and to date my query hasnt been resolved. I emailed there complaints department as well and no response from them either. This is also goin to affect my credit record because of their negligence.