No 4G network coverage in my area but expected to pay

I informed supersonic of my relocation and asked if I should cancel my service as I have been struggling with network since 1 May. I was advice not to cancel as the matter is escalated to mtn. After a week of no response I then decided to cancel the service and apparently they will charge me for next month as I am supposed to give 30 days notice. This is unfair because they advised I should not cancel on the 1st of May and I have proof, now they are telling me that they will charge because I was supposed to put 30 days notice. How do I pay for service Iam not getting, there is no coverage in my new area even after the network was unlocked what am I paying for exactly. Super is a month to month service that one pays for a monthly service upfront, now that I want to cancel my service they are referring Supersonic services to a contract. This is ****. I can't be paying for no service. There is no 4G coverage and that it's not my fault. Why did you stop me from canceling the service on the 1st of May and all of the sudden you tell me about 30 days notice. My 30 days started on the 1st of May so I need my service to be canceled end of May. I can't be responsible for no COVERAGE and you can't penalise me that there is no coverage of 4G where I stay. I have proof on all the conversations where I was told not to cancel as from 1 May until I decided to cancel my service as I see this problem of no coverage can't be resolved and I can't do my work without internet.