It is okay if I want to get even or at least get my money back?
Do you have a way to prove that your money was taken?
No, but I know what happened.
You should not make a plan for getting even with someone without proof. You could end up getting back at the wrong person.
I probably could but I'm not telling.
Find your proof of their wrongdoing and then you can take action. Confront them and demand they pay you back or you can take it to a small claims court for further escalation.