Help me!

I just got my amp and 6 of the channels sound great..... But the left surround channel is screaming at max volume with or without an RCA plugged in. It sounds like DC but I don't hate any speaker I own enough to plug in for more than a second. I have contacted the seller but really I know where that is going to go money off or ship it back for a refund and then I am out the shipping back. Outlaw is closed today so I can not get an estimate on repair for one channel, Any ideas?