WHAT WOULD HAPPEN IF A EMPLOYER WILL NOT LET U WORK AFTER A DR. RELEASED U

If you qualified for FMLA and your absence was covered by FMLA, and you got a full release from your doctor, then the employer would need a very strong reason for not letting you return to work. It is possible that your duties are such that the employer may have a reasonable concern, depending on your medical condition and your job duties.  But this would have to be a real and valid concern with objective medical evidence. I suggest seeing an attorney