Can't make any calls

On Sunday I noticed that my my MTN number is no longer in full functioning. Icould receive call but nit make any outgoing calls or messages. I then went to MTN to enquire, but they could not assist with the problem.I called Viva plus where I initially made the deal of a funeral cover and cancelled the policy.But mobile plus did not allow me cancell, stating that I must pay R900, 00 cancellatioin fee. I asked the operator for the recording where I agreed to pay such in case of cancellation, she refused