Martin Logan Quest need help

A year ago my Martin Logan quest, while playing Patricia
Barber cd, I notice the left channel volume is getting,
lower and lower,then the next day the right channel.
then the sound I notice it goes up and down the panel.Every
help is needed here, If you also know who to contact at
Martin Logan please give me the number.By the way the amp
is ok,tested onother set of speaker, went ok.