MTN Network Tower issue - 3weeks and counting

Reported a problem to MTN. I received email acknolwedgement with a reference number SMC/*** for a network tower that has a fault. I have followed up and the response it that it is being attended to, however 3 weeks later and the "fault" still has not fixed. This is a contract for Data only which I need for work, and this is causing issues for me. I feel under these circumstances I should be allowed to cancel the contract as I am not receivng the service I am paying for.