Ms Dyasi WiFi contract

Please assist I have a problem with Vodacom in capegate mall, I had a WiFi contract with them that worked for only 2 months during the night and not working during the day. Went to the shop to complain, they booked it in for the whole month to repair the problem but it came back the same no change; on top of that they debted me for that duration. Again I went back to the shop to complain the technician told me there is nothing he can do I must call Vodacom offices, I did that but I was not helped but they keep on debting me; I then decided to take the WiFi router back to them and cancel the contract 2 months ago but even now they still debit me every month. Please assist