Received the Receiver, but will have to return

Yesterday I received the most anticipated stuff - the onkyo receiver that I had ordered. It was a refurbished one to begin with...that's why it was cheap also. But I heard this high frequency hiss when I plugged in my headphone. It was simply absent from my other more expensive harman kardon receiver. Of course, you get what you pay for. So I decided to live with the hissing sound. Then all of a sudden the power hum started coming from the receiver. This noise was like a swarm of bees surrounding you. I couldn't take that. It was noisy enough to get your attention when you are playing some music. That was a big bummer. I had bought a pair of Polk R30 speakers from Fry's almost a month ago in anticipation of getting a decent receiver so that I can plug in my keyboard into these things. I am now disappointed. I have waited too long to replace the existing music system with a nice receiver and a set of nice speakers. Should I just go and get another mini audio system. May be that'll do the job. But I don't have much time to return the speakers either. When I called up customer service to return the receiver, they said I'll have to wait until they send me a return lable. Crap!