Can not play back 4-channel PCM

Although the display shows 4 channels (L / R / SL / SR), is issued only to the front speakers. Whether the signal of the rear speakers gerlegt to the front, or simply not play at all I have to check.
In my previous device, the VSX-1122 4-channel working properly.
After demand for Pioneer saying when -VSX-924 is probably installed Other Hardware, and therefore it does not work and 4-channel is rather a rare format, and that the signal of the rear speakers is probably just neglected.
I say, a multi-channel receiver has to pass the PCM signal which he gets without thinking to the speakers - basta.
The receiever has a defect, but Pioneer says: That's the way !!!!!
Must probably my legal turn to the money for this bad buy to get back.