I lost against a couple of cheaters and I did not get my points back, why?

Furthermore, they keep their ratings: @patatarte.
http://en.lichess.org/@/willymouse.

I thought since the rating changes we can recover the points we lose against cheaters. I asked yesterday on the Q & A site but I did not receive an answer.

Regards!!

Because just "giving points back" doesn't really work if you have any understanding of how ratings work. Rating points aren't like money where they can be "returned" if stolen. It's not that simple, it's a complicated mathematical system where all games and ratings are embedded with each other.

The only way to give points back is to recalculate ALL ratings with cheaters removed. This was done a few days ago and took about 4-5 hours to perform. It won't be a common occurrence.