What do you do?

^ What he said. Keep after it.

You pick pocket his wallet and buy him lunch with his own money.

You report him for cheating.

Stop playing chess.

Play other games. May be you are good at FPS or other strategy games.

In comparision with other strat games, chess requires years of hardwork to build up.

Some good players might have studied >10 years and have Level 100, and if you are new to chess ,you might have level 3 or 5.

Unfair competition.

Don't worry; be happy.

I WILL GIVE YOU THE LEGIT WAY WHAT TO DO IN SITUATIONS LIKE THIS :-

1. LET HIM WIN.
2. SEND HIM A REMATCH AND THEN RESIGN.
3. SEND HIM A REMATCH AGAIN.
4. AFTER SENDING HIM THE REMATCH JUST SHUT UR MOUTH AND PLAY THE GAME.
5. BY FOLLOWING THIS STEPS YOU WILL WIN THE GAME.#LEGIT WIN

Don't worry about it man, just play the best moves you can, figure out where you went wrong. I was violently beaten and kicked around (metaphorically, of course) at my chess club for the first year I started playing there. Now I'm starting to get some significant results after 3 years. Just focus on your own development and don't compare yourself to other people, especially in chess, but just generally in life. There will always be someone who plays better moves than you, who gets a bigger income than you, et cetera. Just work on what you have, look where you want to be, and you will get there eventually. Everything takes time.

Learn from the game after it's done, and improve as a result.

Play at least a 50 move game with him. (try to survive that long)

Analyse it. If he plays perfect/ close to perfect, report him.

Otherwise, find his weaknesses.

If he's a bad defensive player, attack (and vice versa).

If he's positional, play tactical lines (and vice versa).

Don't drink alcohol, I made that mistake and lost every game, but I wasn't half happy, hick

FOLLOW MY LEGIT STEPS THAT'S ALL YOU HAVE TO DO