You should absolutely continue this pursuit, but keep in mind that the biggest things you can do to avoid a legal dispute are to clearly communicate expectations and not work with assholes. A well-written contract is like a solid deadbolt on your front door: it’ll make reasonable people think twice, but a determined attacker will just smash a window and go through it (or, to explicate the metaphor, sue you anyway knowing the legal process itself is sufficiently painful to wear you down even if they don’t have a case).