Vodacom Fibre

I got a vodacom router from vodacom agents and I used it only for the trial period which was said to be free and I would only pay if I was satisfied with how it was working but I was very disappointed because it was not working properly the network was going on and off and I ended up switching it off in less than a month and I wrote an email for them to cancel the subscription but they never got back to me this was last year July so now today vodacom took money from my account as a "debit order" I'm surprised because I canceled the subscription I'm very disappointed I even went to a Vodacom branch near me they could not help me.