False advertising

After signing up with Afrihost, it took almost 2 months for my line to be installed by Vumatel, once vumatel installed, my line was activated, I was on the 20mbs line at first, but then downgraded, later I moved to the 10mbs line because the 4mbs was too slow for us, needless to say every now and then the line goes off for no reason and none of us can connect. About 4 months after installation, i got a call from Vumatel saying I must pay for an invoice for installation. I said it was supposed to be covered by Afrihost, even the wording on the invoice I recieved said Vumatel installation. It has been over a year of being with Afrihost and now Vumatel is calling me saying Afrihost is not paying, but I have never even received an invoice from Vumatel, nor am I aware of one, i would have paid when they installed had I known, but it was never mentioned. How can Afrihost advertise free installation up to R4000 then exclude Vumatel, but your invoice stated vumatel installation, this is not fair to the customer or Vumatel. As for Vumatel, how can they install without making the customer aware it is for their account?