DSTV price-lock - enough to get a heart attack

I've got a dstv decoder, and they offered me a price-lock deal with an extra decoder for R49. I've paid for this now twice, and still the second decoder is not working. I've phoned and they keep on telling me as it is a price-lock, they can't put me through to them, I have to sms them. Which I've done now a couple of times. Today they informed me that the 2nd decoder has not been linked on my profile so I'm suppose to go to the closest dstv to correct this. Why am I suppose to fix their mess up?