Need help in reporting hackers

Or just, you know, don't play with random people but with friends?

How exactly does it affect to you? I mean, it's not competitive or anything.

Meh.

you should report to both Steam and Overkill. There must be an email contact on their website.

This thread, scroll a bit down. :)

I think that's a bug/exploit and not a hack. I remember playing with Raiden once, he did the same thing with placing a crapload of sentry guns and i'm pretty sure he didn't use any hacks whatsoever