I am a pro se Plaintiff in an ADA suit against a local government. I want to call former co-workers as witnesses but they are afraid of testifying for fear of retaliation. The particular office I was in had a long record of grievances from employees because of unfair actions by the management of...
If the medical certification was late because of delay on the part of your physician and not you (which seems to be what you are saying), then you have a basis for a lawsuit.
Good luck.