My MacBook Pro is not getting turned on

I have my MacBook pro 13 non retina with 4 gb ram 500 hdd . It was working fine and suddenly one day, its not getting turned on. I went up to the service centre and told what happened. They just reinstalled the OS and formatted the mac. And it was turning on after the service and I brought back my mac. Now its 2 days after the service and I face the same issue of not turning on. What should I do