How Long Do I Have To Be Her Bank?

Location: Arizona. My ex wife has been paying me child support by employer withholding since my youngest son was 4 or so. He graduated HS in 2022. I told her she needs to stop the payments. I do not want to be responsible for the money she sends me. She said it's my responsibility, which I know is absurd. However, I have reached out to a paralegal who said to give her their information and they could help her with it. She never contacted them.

Recently, I talked to an actual attorney who said it would be easiest and quicker if we filed it ourselves. They pointed me toward the documents on the county clerk's site that we'd need and let me know how much the filing fee would be. I downloaded, completed and printed the forms. I put a post it where she had to sign and another where she had to sign and get notarized. I put it all in an envelope with another postage paid envelope. There were zero excuses for her not to do this.

A couple days later, I get the packet back. She signed in the signature only spot, but the notary notarized the second spot without my ex's signature! Blank signature line, notary signature and stamp all present. It's now been over 2 weeks since I advised her of the error and she said she would redo those specific pages and mail them to me. I haven't heard from her since.

I have tried everything I can think of to get the money to stop. Odd problem to have, I know, but I don't want to be responsible for all these overpayments. Don't ask why she doesn't stop it, I don't know. Maybe she hates money.

How long am I responsible for managing this money she keeps sending me?