Paying for a LTE package from MWEB that doesn't even work

I signed up with MWEB for LTE on the Cell C network in June 2018. The main reason for applying for the LTE package was for the DSTV Now App & to use it for WiFi. My account has since been debited 4 times. From the first day I received the device & simcard, I could not watch tv as it buffers every 10 seconds and I've been having issues with my WiFi & we only have 2 cellphones connected to it. After going back & fourth, MWEB advised that my house has bad coverage on the Cell C network & now want to offer me a other network for more than what I am currently paying or less & then get less data. My issue is, when I signed up, MWEB should've checked the coverage in the area & at my property & then advise me accordingly as they are the experts. The salesman was at my house more than 3 times already & has only afterwards checked the coverage & then told me the coverage at my place is bad, something which I cannot be held responsible for. MWEB has since told me I've used data every month & they cannot reimburse me for something I've already used, however, I was told that the device automatically updates regardless if it's on or off, which uses data, my daughter who is 2 years old watches cartoons during the day & it buffers every 10 seconds, so obviously it will use data. I've requested for this service to be cancelled & now MWEB wants to charge me a cancellation fee, something which I was told by the Sales person that I can cancel at anytime & not pay any penalties. For over 2 months now I've been calling, emailing & even went into MWEB's offices & still my issue hasn't been fixed. MWEB does not provide any email addresses and when you call them you spend minimum 10 minutes on the call just listening to the voice prompts in the background before anyone assists you. I've requested a refund for the 4 months that they've debited my account, which they've declined. MWEB's offering me a other service provider at a discount but still it comes at a cost of either I pay more & get more data or pay less & get less data, which doesn't make sense. I'm sure I am not the only client who has been experiencing this.