Wrong, its a single channel with an extra positive and negitive teminal as a convinence so you dont have to try and cram heavy gauge wires into only one set.
Also I have delt with Sonix on this same deal with the same amplifier with these same issues just get your RMA and get another one I ended up getting one that worked well and the buyer who has it still beating up on it.
You have options if you have money you can buy another one with there buy back return deal, you buy the replacement then once they get the RMA return and tested as defective they credit you the 209.99 or what ever you spent on it.
They did this for me and I never had to pay a 10% restocking fee, that only applies if you are returning the amp if you dont like it/wrong product, not for a DOA product that neither you or them have ANY way of knowing, charging a 10% restocking fee on defective DOA items like that would put them right out of business.
FYI had 2 1500d from them DOA 3rd time was a charm.