I'm going to ignore my childhood friend because he's been dishonest with me too many times
What is your friend being dishonest about?
He was dishonest when he wanted to use my smartphone. He was just using it to feed his gambling addiction.
Honesty is extremely crucial in friendship because all friendships are built on trust, honest friends inspire & motivate us, and they boost our self-confidence by having trust in each other. Talk to your friend rather than ignoring him so that you can both learn from the experience and continue to be friends.
My problem is it's not over. I wish I could forget about it but I just can't.
Well yes I agree. Ignoring him is not going to fix the issue whatsoever. Do your best to converse and find a way to mediate the behavior that is causing your frustration.