This sucks

I was checking out my FTP rakeback and saw that it was negative. I sent support a question and this is the response I got:

You have $xx.xx in tournament overlay deductions. These come from either Iron Man, freerolls or playing in MTT's that had overlay. They deduct your share of the overlay from your MGR which created a negative rakeback.

Well that's just stupid. I have to pay for their overlays and freerolls from my rakeback? How does that make any sense? They promote a guarantee and when they can't fulfill it, they take my hard earned rakeback to pay for the overlay?