Shoddy Connection and Technical Service

I have had Cell C LTE connectivity at home now for the past almost 2 years. I originally purchased data on a special they had that cost me R 1500 for 100 Gb of data for 12 months. I have been very happy over the past periods so i recently purchased 200 Gb at R 2000. Connectivity was fine for a short period, but the last 4 or 5 weeks i have had no connectivity at all. The WiFi modem connects, but all my devices keep coming up with a note ' No Internet Access Available'. I have placed numerous calls (at least 4) with Cell C ( ********** 555) technical but still nothing has been resolved. I am now at my wits end. I still have 135 Gb of data available and all i want is the equivalent money back so i can go to a service provider that is more competent in sorting out technical issues. I use this connection for work from home and the past weeks, this has not been possible ... I tried to download a movie on DSTV that was 650 Mb and it took 16 hrs to download because the the internet connection kept dropping. This is ridiculous and totally unacceptable Cell C !!!!