WHY DO I HAVE TO PAY FOR SERVICES NOT USED????

I upgraded my DSTV decoder to a explora decoder which was easy - Delivery happened promptly!!! My decoder was delivered on 12 Jan, multichoice INSISTED I use their installers, (as installation was part of the special) which will only be available to do installation on the 21st of Jan - Which I accepted!!! Next thing I know I got a call from multichoice requesting me to pay for the explora service from the delivery date, I explained that we have not used the explora services yet as the decoder is not yet installed, because the installers can only come do installation on the 21st. The person from multichoice told me that I have to pay for the service from the delivery date of the decoder - How on earth does that make any sense??<br> Please can someone explain to me how this works??? I REFUSE TO PAY FOR SERVICES NOT USED!!!<br> I EXPECT A REALLY URGENT RESPONSE TO THIS!!! I have had no happiness since this thing has been delivered.