Audio OFF

[Suikam]

The Mark Levinson audio system of my GS 350 has no audio. It always turn on with Audio Off and there is nothing I can do to have audio. So I cannot hear any music, however I still can use my Cellphone bluetooth and have a call thru the speakers. So this is very weird. This showed up after replacing the car battery but I had audio right after battery replacement for 1 day. So suddenly it stopped working. I have read many threads on checking the fuses, rebooting the system and disconnecting the battery, I have tested all these suggestions but nothing has worked so far.  I just cannot believe that just by replacing a car battery will damage the amplifier.  However, I think that if the amp is damaged, why can I still have a phone call go thru the speakers ??  Any suggestions will be appreciated.