Sorry to hear that you are going through this. It does sound like they have paid you but that the amount is not correct. I would enter the 1099-NEC. I would then backout the amount you do not agree with as an other miscellaneous expense. I would request documentation from the company that issued the 1099-NEC that will support what you have done on your tax return. I would maintain good records to support this adjustment.
You can also contact the IRS for help but this may take longer with the filing deadline approaching.
https://www.irs.gov/newsroom/what-to-do-when-a-w-2-or-form-1099-is-missing-or-incorrect
