FMLA Question.. Can a supervisor require you?

Ok FMLA intermittent is approved and all paperowrk in order to care for a family member that was injured recently. My supervisors are giving me HELL about questioning me about what I am doing on the days I take off specifically what I am doing. Most recently forcing me to write a memo time stamped with a run down of what I specifically did ove r the past two days off that I took on FMLA. Can they do that? I thought that was strictly forbidden under FMLA? I thought if it was signed, sealed and delivered through human resources that they couldn't even question you about it?? Anyone have any knowledge in this area? (and no I am not abusing the FMLA status..where I work they are just micro managers)