That's... not possible... is it? You can't file contempt for an error in filing and then ask for back CS. Especially if it was done through legal channels. You can ask for a modification based on the fact that new information came up that there was an error. Because I'd head straight back at my lawyer and BM's lawyer during that filing period and sue them for the 78 grand that they caused me to have to shell out now.

What backwards state are you in that would allow this? 'cause we'd be sueing BM for contempt for lying about the daycare costs and getting back money DH gave towards it.

I kind of had a similar situation from the BM perspective. Because of a clerical error in MY state, HIS state only went after him for current CS and not arrears. When the error was found out, his state would not do anything about it because of their law.

My state's lawyer ended up writing up a proposal with a low-ball amount (IMHO) for arrears. Surprisingly enough, the NCP signed it. I think he knew if it went to court, it would be a much higher number. His lawyer must not have realized that, legally, our hands were tied.

In your situation, if it is just a threatening letter, do nothing.

BM pulled the same crap here during the custody dispute. Threatening letter with a "generous" offer to forgo court proceedings if he agreed to $x more child support per month. DH handed it off to his lawyer who laughed, then called him back after she ran the numbers to point out she had found several anomalies in BM's original documents, such as BM going from a sales commission based pay on joint taxes to "receptionist" with no commission making less base pay at BMDaddy's company at the time of the divorce. DH's lawyer told DH to completely ignore the letter and that if BM pushed it forward then DH would be able to go after her for fraud.

DH ignored the letter and it never came up again. Even when the new child support was calculated BM never brought up DH's supposed arrears.