A pending legal action could put the acquisition in jeopardy. I'd expect that they would take any credible legal threat very seriously. See if you can get a l

A pending legal action could put the acquisition in jeopardy. I'd expect that they would take any credible legal threat very seriously. See if you can get a lawyer to write a threatening collections letter. That may be all you need to get them motivated. It shouldn't cost you very much to get a letter drafted by an attorney. It took my lawyer about an hour to draft a similar letter in the past, so figure 1-2 hours times your lawyer's hourly rate.