No service and no communication

Since the 28th November I have been sending whatsapp messages asking them to cancel my service as i was a new service provider. They respond with can they not change mind. I told them no cause i have been without service and was told i will not receive any refund for days without firbre. Now they not responding to my messages at all. I havr a new service provider but they cannot proceed until they cancel but they refuse. I feel like im being held hostage