DStv Explora - nightmare

My son-in-law and i both bought the DStv Explora in August 2013 at a cost of approximately R5000-00. Since my son-in-law was staying with me and had a debit order with Multichoice, he paid the subscription. My son-in-law recently moved into his own place so i had to take out my own subscription. Recently i kept on receiving messages that the hard drive on the Explora was ******* but could not correct it. I took it to Multichoice on 12 January 2015 to sort out. They confirmed that the hard drive was ******* and that they could not repair it. I was told that the Explora was working but without its full functionality. I contested this saying the Explora was not designed to view in HD only and that if it could not produce its other functions, it was indeed disfunctional. I was told i would have to pay over R500 for a replacement Explora. They were not prepared to honour the 24 month waranty since the Explora was transferred from my son-in-law to me. This, according to them made the decoder second hand. This according to the rep was policy. However, my subscription remained the same. Since this is their product i think that this is grossly unfair.