Interupted service

I have been unable to phone calls on my phone, When i called the call center i was told i needed to wait for 72 working hours before they could try sorting me out, i asked to speak to a supervisor but she wouldn't come to the phone and promised to give me a call which she never did. I have air time on my phone but every time i make a call it says i have Insufficient air-time to make a call. I only have one phone and right now i can not use it and my service provider is doing nothing about it.