Anyone with Major Account Collections Experience/Recommendations

We have a (former) key account that still owes $45K and has been over a year after a contract manufacturing job. Deal was with CEO, then COO and then CFO, all of whom have left/been kicked out and is now with a restructuring group (not bankruptcy) after their last investment round probably didn't meet target goals.

We get plenty of non-specific responses to our inquiries but are just getting strung along. New guy is just stringing us along after several good faith offers to work something out. I've grown tired of chasing while trying to grow the rest of the business 100% Y/Y. The $ is important, but the time already spend on chasing this is also costly.

Does anyone have a reasonable recommendation on a trusted agency or person (or strategy) to pursue?

Email/phone or posted responses are all welcome.

Thanks -

Paul