Refusal to pay installer for Explora Installation

I accepted the OnAir offer rather begrudginly in July last year, pointing out to the consultant that i would not be installing for some time due to moving house and renovating. I was contacted a number of times after that, following up on installation. On these occasions I again reiterated that I would only install post-renovations. In January this year, I contacted my local installer, who installed and submitted the invoice to OnAir. I was again contacted by a consultant at the time of installation, and she confirmed that I need to give the voucher to my installer for payment of installation.<br> My installer forwarded an e-mail from OnAir, wherein they refused to pay for installation stating that the voucher had expired. Countless attempts to contact them, and when I did, was told to lump it - they were happy to remove the Explora at a cost of +_R300. My Installer is holding me responsible for the account - I would never have accepted the deal if I knew that over and above R149/pm x 24, I would need to pay more than R1900. I e-mailed the consultant's manager months ago, no response to date. MULTICHOICE NOT INTERESTED IN HELPING