I find this even less likely.. These people aren't going to talk to customers and slam their own products if they value their jobs. Much of customer service in many companies is monitored, they aren't going to say things to slam their company or its products, the most they should do is try and resolve your problem, and if they suspect a defective product, setup a replacement.
If you really suffered a 90% channel loss from one box to another, and nothing else has changed, I would suspect a hardware problem and ask for a replacement.