No anti-money laundering law doesn't work that way
> The fact that they stop the contract so soon without previous warning (unless Librapay is not disclosing everything) is what make it really weird for me.
That is completely normal (in fact giving notice is pretty lenient), if a financial institution suspects you of money laundering weird things will begin to happen to you such as freezes, orders being ignored, surprise account closures, etc. You will under no circumstances receive an explanation as that in itself is a serious criminal offense because it is considered to be helpful to money launderers when you explain to them what they did that aroused suspicion.
Note to readers: if weird things start happening to your bank account (delayed or ignored payments, logouts, etc) get on the phone to the bank and be as helpful to them as you can be. That is typically the only way to get this resolved.