Retainer

[NH Mom]

What is the name of your state (only U.S. law)? NH
Three years ago, I retained a lawyer to try and get child support for my 2 children. The lawyer required a $750 retainer, which I gave him via check. It was all of my savings. We had one meeting, after which he filed for discovery with my ex's lawyer. I spent my vacation completing all that copying and paperwork. At our next meeting, he informed me that we would have to wait 9 months more before filing, because the previous uniform support was still in effect. And it could cost $2500 or more. If I waited the 9 months, I could not recoup $2500 in child support before my children both turned 18! I was angry and wrote a letter asking for any remaining portion of my retainer to be refunded. I've called a few times over the years, but have still never received an invoice, or any correspondence. What recourse do I have? I was never told that this was a non-refundable retainer, and the lawyer should never have encouraged my case to proceed without looking at the original uniform support order that was issued while I was previously under his council. The one time I did reach his secretary, she told me that my case was "in a box in the attic" and would have to be dug out.What is the name of your state (only U.S. law)?