My screen doesn't work and the phone is locked, how can I get into my phone?

[AC Question]

Screen doesn't work and phone is locked

Okay I have a Samsung A3. I dropped it and the screen stopped working, it is locked. In a day the screen is dim with some black spots. Now I want to switch it off but due to the screen lock it is not helping. I can receive the calls and sms but the screen does not pick up my touch

I have tried to look up on the videos and info, but it is concerning S3 where you can remove the battery. A3 does not have that facility.