GIVSP
Agree with you, but the issue is if the company do not wish to pay, then that's it, game over.
BBC recently said if new legal cases were to be put on hold it would take 350 years to clear the backlog. You can forget about any legal action. This is the reason for my warning, it has to be money in advance for this company.
And in answer to your question, no, not a crew visa - an employment visa - as that is required for a validation. (FATA)