Car had the original Concert Cassette tape radio/ Bose system for 10 yrs.

A few months after installing a Pioneer Headunit + Bose connectors ( which I can only describe like a battery for a radio control car) , the rear right passenger speaker has no sound at all.
The specialist who fitted the unit troubleshoot by checking wiring and also taking off the door card to inspect speaker and also connecting a spare speaker but still no sound.

He reckons its the Bose Amp and must be replaced by a Bose brand which may be a problem to locate one.

Anyone has any ideas and my options?