This is a lesson I learned many many times in life.
When cash leaves your hand, the chances of you getting it back are slim.
Whenever you rent an apartment, what happens? You put down a deposit to the landlord (who probably has more money then yourself). When the lease is up and its time to jet, even if the apartment was cleaner then when you moved in, 9 times out of 10 the landlord will try to keep your deposit.
Whenever you have a roommate, I would say 75% of the time they will try to rip you off at some point during the tenancy.
When you work an actual job, at some point the employer will try to steal away your time. Make you work beyond your job description and have you work for free.
Well, the list goes on and on. Remember the above valuable lesson.
The only *chance* you have of getting your cash back once it leaves your hand is if you act immediately and aggressively.
Immediately means just that. As soon as possible.
Aggressively means that you get in someone's face until the police arrive or filing a lawsuit that day. If its an employer, file a labor claim with the state that day.
Even then, its only by chance that you will receive your cash back.
This lesson applies to ALL people, everyone. If you give cash to your brother, there is a chance it wont get paid back. If you give cash to your best friend, there is a chance it wont get paid back. etc.
Your money should not be handed over to anyone. If you do decide to hand it over, then there is a good chance that you wont be seeing it EVER again.
Even if you signed a contract, the only way it can be enforced is by a court order garnishing wages or confiscating money from a bank account.