Multichoice put customer at their mercy

I purchased a DSTV explorer from Makro with an Blingstallation voucher. Little did i know that they are the only people that do these installations and that i am now under their mercy. I phoned to schedule my installation and requested a late afternoon installation as i am at work during the day as we all are. I received an sms confirming my installation 2 days later at 10 in the day and was told that was their rooting and nothing that the telephone consultant can do. I rescheduled and requested another later afternoon or weekend. This time i received a 8 in the morning Monday time. 3 weeks on from my purchase. I dont understand why if i am the customer paying for a service i get dictated who to use and at what time my installation will yake place.