Hangs a lot. Review on Samsung Galaxy Grand

I bought it in 2013. For few months it worked well but afterwards it started working very slow and gets hanged each and every time I start using Internet. Even when not using Internet it is so much slow that it takes 45 seconds to open up just Contact Names or Gallery or any other thing. When a call comes the screen becomes full black and did not show the name or the swiping icons to receive the call at least for 15 seconds.I restored factory settings many times but it did not work. Worst phone I ever used. It was of 20K when I bought it so I cant sell it just for 3-4K. I am pissed off after buying Samsung Products every time. They are more than worst. Go for any other company like Micromax. My many friends are using Micromax Phones with Lollypop Mode and they are working very fine. Never hangs up and Internet Speed is amazing.