Afrihost / Vumatel "Free Fibre Installation" gimmick

In March 2018 I app**** via Afrhiost's customer portal for a Fibre Installation in my area which was outsourced to Vumatel. Afrihost's application system clearly showed that the installation costs would be negated i.e. "Free Installation". Fast forward a year and I am now being harassed on a daily basis by Vumatel's accounts department who are claiming that I am liable for the installation costs. When I asked them why they sent me an invoice almost a year later they claim it is because I don't respond emails and apparently they had emailed me the invoice a year ago.

Logically if the installation costs were for my account then why to date have Afrihost not raised these costs on my monthly billing ? Furthermore I do not accept Vumatel's lame excuse about "sending an invoice a year ago, but I never responded" because logically if I owed them the installation costs and they indeed sent me an invoice a year ago why have they taken a year to follow this up ?

I have researched this and found several other cases where Afrihost has advised "Free Installation", only for Vumatel to claim installation costs down the line. It would therefore appear to me that Afrihost is being highly ********* in this regards and duping customers into thinking the installation is F.O.C., when in reality they are not honoring their promise of a "free installation". I therefore welcome Afrihost's feedback in this regards as to weather the "Free Installation" is merely a gimmick and if not, then Afrihost needs to pay their installers such as Vaumtel so I don't get harrassed on a daily basis for payment.