This is likely not the answer you want, but it’s the only one you’re likely to get. That is, if you have proof positive of cheating/hacking etc, you can (and should) report it (instructions here: Found an Exploit? Here's how to report it!).
Alternately, if what you’re experiencing falls under harassment/griefing rather than technically cheating, this is what you need: Harassment and Griefing Issues