A6 mmi problems

Hi everyone I'm new to the forum,really hoping to get some help and advice with my car if possible. The car is an A6 C6 Avant and been having lots of trouble with the MMI. So one day everything stopped working and I traced the fault down to the control head and the amp,I replaced both of these and had the component protection removed at a local garage. I also made sure I matched the part numbers when I replaced them. Now I have no sound from the radio,the cd player/changer recognises their are discs in their but is constantly stuck on pause?? Everything else works but the only sound I get is from the sat nav or the Bluetooth to make and recieve calls. The only difference I noticed is that thd new control head appears to have come from an A6 allroad im guessing as it has the suspension settings which the avant obviously doesn't have. Does this mean the control head might be the cause of the problems as it could be using a different software? Completely run out of ideas how to sort this and hoping the more experienced guys on here may be able to point me in the right direction,I have access to vagcom and can put the scan details in here if needed,thanks in advance for anyone that can help