Unfortunately, this happens more often than you think.
My wife got a job at a frum girls’ school. She was told a salary she’d receive, and asked for it in writing. The principal refused – he said “My word is enough for me, and I’m an honest person.”
When it came time to get paid, my wife received far less than she was supposed to get. She confronted the principal and he told her he would never have agreed to pay her the original amount, as it was too much. My wife told him she wouldn’t have taken the job had she known the salary would be the amount she was paid. He told her it was her problem, and she could leave if she wanted. She told him, :This was why I wanted it in writing. Obviously, your word is not as strong as you claimed.” We contacted a Rav who referred us to a Beis Din. We were told not to go to Beis Din until the school year was finished, so she wouldn’t lose her job over the issue, and we’d be able to get back all the money at the end of the year. For the next few months, the principal made my wife’s life miserable. He treated her terribly, constantly yelled at her, etc. She ended up quitting.