Mondo / Telkom Bad Service

I ordered a modem throw Mondo after they told me we have coverage on the farm for the 4G Modem. After receiving the modem, I found NO coverage at all. I phoned them to cancel and they did accept it. In October 2019 they received the modem in good order and confirmed all is in order. But up and until now in March 2020, Mondo/Telkom is still deducting a debit order 3 times a month. Leaving me with a red face. When I mail Mondo / Telkom about my problem, they say they are still busy with the cancelation.......... 5 months to cancel a debit order. Serously?