Does it safe to send mac to authorised store for service?

Hi everyone,

My MacBook Pro has some system problem(screen brightness control disappears n also the auto graphics switc) so I need to send back to an authorised store(I live in Malaysia there has no a single apple store in my area) to service and BTW my MsacBook still under warranty coverage, but the problem is my friend notebook which is fujisu having subwoofer problem after getting back from service n I also heard some true story too, so am I need to send back or just solve it back my own(redownload os x)

Because that shop is a authorised store but I can't trust them will care my mac!!!