JVC TH-M606 so many problems

Question

First I would like to ask why the sound keeps cutting out. I can not turn the machine past 10 without the connection in the back cutting off. THe green light goes out and the sound is lost. I have gotten this from RENT A CENTER and they have taken it to the shop 3 times and replaced the faulty connection and blame it on JVC design saying that all the subs are like that? How can I get this to stop shorting out? and another thing I need to get a code for my universal remote( NOT JVC but a SRU4040) because REENTACENTER failed to return my original one and now has no replacement that work?