Bad follow up technical support with Vumatel.

I have been having issues with my internet dropping consistently for the past three weeks and every time I get through to the call centre I go through the same processes of rebooting my ONT then getting a message and to date it is still not working properly. I have made today alone 7 calls and two call backs of which I am still waiting for a manager to call me back. My work is lagging behind, my daughter is battling with her assignments and all I get is an SMS of three working days of which I have received 4 since last week and no improvement. I was told it is not the ISP but the line but if this is so why has a technician not been sent out as yet.