Happens to me all the time. I run an online football management game, and there are a lot of children who play and think calling you names is a reasoned response to an issue.

The thing is, you don't let it get to you or even register it. They pay you money, you deal with it. That's the way it works.

Also, I've never once told them it's not very nice. They know it's not very nice.

I've turned paying customers around from "Fuck you" into "take my money please" by just responding to the issues they say around the insults.

Here's an example.

Customer - "One of my players was cut off my team, this fucking game is stupid and I'm never going to play it again. FUUUUUUUCK YOUUUUU"

Me - "Wow, that sucks to hear. I looked over your team and it looks like you signed 1 too many players, and it had to find someone to cut. I can go ahead and reassign him to your team if you'd like, but you need to specify who so you aren't over roster limits."

Customer responds with who, and thanks me.

Completely normal. No big deal, don't let it ever get to you.