I did some research and located this info on the DOL website which supports my side. I am wondering if it will be worthwhile to sue
Section Number: 825.311
(b) When the need for leave is not foreseeable, or in the case of
re certification, an employee must provide certification (or
re certification) within the time frame requested by the employer (which
must allow at least 15 days after the employer's request) or as soon as
reasonably possible under the particular facts and circumstances. In the
case of a medical emergency, it may not be practicable for an employee
to provide the required certification within 15 calendar days. If an
employee fails to provide a medical certification
within a reasonable time under the pertinent circumstances, the employer
may delay the employee's continuation of FMLA leave. If the employee
never produces the certification, the leave is not FMLA leave.
The law mandates a minimum of 15 days but, per Section Number: 825.305
(d) At the time the employer requests certification, the employer
must also advise an employee of the anticipated consequences of an
employee's failure to provide adequate certification. The employer shall
advise an employee whenever the employer finds a certification
incomplete, and provide the employee a reasonable opportunity to cure
any such deficiency.
(e) If the employer's sick or medical leave plan imposes medical
certification requirements that are less stringent than the
certification requirements of these regulations, and the employee or
employer elects to substitute paid sick, vacation, personal or family
leave for unpaid FMLA leave where authorized (see Sec. 825.207), only
the employer's less stringent sick leave certification requirements may
be imposed.