Not Honoring Our Deal

I've been with Webafrica for a year now, recently I called in telling them I want to cancel my Fiber Package as there are now tones of cheaper ISPs. I gave them an option to lower my monthly payments so I can stay with them and they flat out refused and said if I can't pay R799 for 20mb download speed I should downgrade to 4mb. Having made it obvious that they don't care if I stay or go I decided to cancel and now they are telling me that I need to send the router back. When I signed up I went through the Ts&Cs and clearly stated that after 6 months the router will become mine, now when I go to their website this has changed as well but it's not the original agreement we had when I signed up. I was going to leave my VOIP line with them but now that they have proven they cannot be trusted am actually canceling everything and never going back. The service was great and that is why I gave them the option to lower my payments, I would have gladly stayed with them but I cannot continue paying R799 when I can pay R650.