Horrible, impersonal and pathetic Internet Service Provider

Been off WIFI for over 10 days this month and logged in several calls on Whatsapp. I tried switching to another service provider and Vumatel requires a cancellation letter from Supersonic. I have called them several times and never reach them as the line always says you have pressed the wrong selection. So sick and tired of buying data when I paid for WIFI and being taken for a ride. All I want is a cancellation letter to move to another ISP and they cant offer that. They are very impersonal and non responsive. Their network has been glitchy for sometime now and I need internet to work. Horrible and pathetic service provider.