Struggle to cancel service

I signed up with WebAfrica for a fibre line (wi-fi) but they didn't state that it will be 5G. After installation and connection, I realized that they make use of 5G, after which I cancelled. They don't provide an email address but make use of WhatsApp. After informing them on 6 July 2022 that I cancel, their "bot" did not respond as expected but there was some WhatsApp conversation which was cancelled due to me not responding, I'm working and can't chat during working hours. So months pass and still I am not cancelled. Due to this lack of service I will not recommend WebAfrica to anybody