Hang fire with the lawyer, go and see them first if you can then you can sort out any issues face to face and don't leave without your money. I've had the same problem with a company that doesn't exist anymore and it was the only thing that worked. Hopefully this is just a blip and you can remain on good terms with the company and hopefully continue to get work but they will know they can't mess you around when it comes to money. It's always easier to fob someone off over the phone or in an email, if you make it clear they'll have to deal with you in person with any further issues they will be less likely to mess you around.
Best of Luck,
D