How do I get my bf to text me back and why did he atop textin me?

Ask him. He is probably just busy, or his phone is going haywire. Find a time to talk to him face to face. Ask him whats going on. If it's just little, keep on going out with him. If its medium, break up for a little while, a couple of weeks. If its big, give up. A couple sadly can only go so far.