Do they really steal our money or????

I was wondering if it happens THAT OFTEN that a player will not be paid because the bookmaker blatantly steals your money. I am not talking here about having to wait 1 week or 2 to receive the money. 

I am talking about NOT getting paid at all and losing all the money. I never had a problem with bet3365 bookmaker ladbrokes bookmaker.eu 12 bet etc. Now, I am with NETBET and I made  a profit of 4 000$ and I just hope that nothing bad will happen. I'm overthinking it I know.

Thanks to all