L4 - fired on probation for baseless reasons, turns out I was temporary from the beginning

My contract was suddenly terminated without being given any good reason. Any thing they said to me was either insignificant, not expected to be known by someone new, or just straight up false. I was made to believe that it was my fault and was escorted out like some kind of dog, after working with these people for months.

I found out later that my replacement was always there, they were just still occupied with some personal development and could not already start with the shift. They were always planned for my shift from the beginning, and I was just brought there as a temporary placeholder. I did a very good job and received good feedback from all my coworkers, and this firing was definitely undeserved.

One thing I still cant wrap my head around is how this makes any sense for them financially, to put someone through the academy and waste all that money while knowing you will fire them eventually.

Unfortunately this was done during probation, and there does not seem to be anything that I can do. What would you guys recommend for me in this position? Is it worth contacting the people who did this to me? Do I have any claim for anything in this situation?

This is in Europe by the way.