What else can I do if my calls to them have been unsuccessful and now it’s time for a paper trail of certified letters?

I recently settled my case (Nov. 2016). However, I was told by the government that there were medical liens my lawyers neglected to pay. When I contacted the lawyers, they were less than helpful, did not want to talk to me and will not call me back. I have a deadline to respond to the government (July 15)- I was told I need a breakdown of the case settlement, which I need from my lawyers. I need the appropriate law or act to write my attorneys a certified letter to release my entire case/files including this information. It’s been brought to my awareness that there is a substantial amount (financial) that they are withholding, never distributed properly to medical liens and me. They paid me, they told me everyone was paid. As of today, the government’s data shows otherwise. The medical claims unpaid shows otherwise. I need help. I was told to get another lawyer. My original case was in June 2013. Five years later, after settlement, I'm told this was mishandling by my attorneys.