AFANK you can return them with no reason if you contact the retailer within 7 days, tho you have to pay the shipping.
Dont Quote me on it tho, sure that Agent will be here soon with a better knowledge on the subject.
Anyway it should (fingers crossed) all work fine.
I recomenend downloading AC3 filter if you listen to music. I did yesterday, and its great, went for over a year using Pro Logic from Vista, and now downloaded this, and wrote my own matrix, so that center mixes right nd left channels, and the rear channels are not that stupid rubbishy sounding noise, but the same as front left and front right. It also has the ability to set profiles, so I have one with the right and left channels duplicated as above for music, and a seperate profile with the matrix standard for films, and a different one with the channels on different gain for watching from my bed