How far into the Past are Points Lost to Cheaters Refunded?

I know if I lost to a cheater a day before they got banned I'll get my rating back, but what about 3 days? 1 week? 1 month? I know about someone whom I had been playing in tournaments for a long time, and who probably cheated for at least as long, but when he eventually got banned, I got no rating back although I played and lost about 10 games to him.

Please note, I'm not asking about whether I can get those points back, I don't really care about them. I was just curious how far into the past the rating refund system can reach :)

I recall the points are refunded for the last 30 games the cheater played.