payment for Installation of Explora decorder

i have a problem, in April I bought a DSTV Explora which came as a package of 2 decoders. I was told that the installation was for free for both decoders, I asked the consultant who was assisting me many times if the installation included both decoders and he agreed ,and even before the installer started working we called to confirm if installation was indeed for free and it was confirmed. The second decoder was delivered 3 weeks later, and the same verification process took place and it was confirmed that installation was for free. But now the guy who installed my second decoder keeps calling me demanding his payment from me, yesterday he came to tell me that you guys are telling him that I need to pay, which I will never do, it recorded , you have recordings of all the engagement I had with you. If this matter is not resolved I am going to open a case at ICASA because clearly this was done intentionally to push your sales figures.