Every A and E flat keys of my Motis xs 7 are death. i took my keyboard to a service center i they cant find the problem.
How can we help you, here? Can you give us anything to go on?
Is this an Authorized Yamaha Service Center? (They need to qualify to be one, and would certainly be able to identify and fix the problem). You can ask them if they are "authorized" for Yamaha service. Often you can find authorized service centers near you, by going to your regional Yamaha.com corporate website - Typically at the bottom of the page - is the "Service Locator" - a listing of authorized Yamaha Service Centers. See attached example from the USA Yamaha Site.
You will be asked what type of product, and your location...