Webafrica Playing Unfair !!!!!

They wanted to charge me installation fees when i canceled their fibre service within one year because i moved, but the installation was not done and was already done when i moved into the unit. On their website when you cancel you have to agree that you will be liable for the installation costs because of canceling within one year. So i was not able to cancel on theor website. Moved to their Wonderful whats app chat where absolutely no one understands what you are saying and are talking to you through copy and paste method. Thei confirmed i am liable for the installation costs i was transfered to managers and a few more people on this whats app chat situation they got going for them all agreed that u will be liable for this installation fees if i have to cancel.. so i gave up and switched the router off the 3rd on the new month, Which means if it gets to it they can only charge me for 3 days used service Once they see it was off and a month later no payment they phoned me and i explained to a very nice Lady the situation. She confirmed the installation was already there and my service with them was canceled immediately and the installation costs was taken away, Now i get threatening emails and messages that they will hand me over if i dont pay the one month service fee. Which is extremely unfair. BECAUSE I WAS NOT ABLE TO CANCEL THE SERVICE, Someone from their Legal department phoned me just to tell me that i I'll be handed over because of the outstanding amount. And the more i explain to her the more she "Just knows" she knows but she doesn't know how to help ... She understands what the situation is but she is not able to help because she only deals with legal stuff..... I have absolutely no problem with being charged for the 3 days in the new month the unit was used. But it is impossible to tell me i owe the full amount, if i wasn't able to cancel and NO ONE from your team whether it is phone email or whats app was able to help me !!!!!!!!!