Various legal firms represent pilots in issues involving the pilot record database. You should educate yourself as thoroughly about the PRD in advance, however. An older set of videos that I've linked before will give you a primer:
https://www.youtube.com/@chrismorris9967 (not my videos)
https://www.faa.gov/documentLibrary/...AA_8060-15.pdf
Only you can dispute any entry in the PRD. Only you can authorize anyone to make a correction. You may grant or revoke permission for employers and former employers to view your record or access your record. An employer cannot simply alter your record. PRD records cannot be deleted. Entries can be edited, and in certain cases, the entry or information in the entry can be suppressed, but changes to the file, and access to the file (consent) must be granted by the file holder (you).
If you dispute your record, the employer has 10 days to respond.
Do you have documentation of your interaction with company personnel about your time off work, sick time, etc?
If you were employed as an at-will employee, either you, or the employer can terminate the employment relationship at any time.
You should consider use of legal services that are familiar with PRD disputes. (Barnetts, Pilotlaw, Aviationlaw, etc).