Can a store manager refuse my FMLA?

I work for Wal-Mart in Portage, WI. My doctor filled out my FMLA and I turned it in. The store manager told me that the way the doctor worded it that she didn't have a position for me. She gave the FMLA back to me and told me that I needed to take it back to my doc and have it re-worded.
The part of the FMLA that my store manager said would end my position is worded like this...

Is the associate unable to perform his/her job functions due to the condition? The answer is yes.
If yes, identify the job functions the associate is unable to perform:
The answer is recurrent lifting, bending, twisting, prolonged standing, if exacerbation.

Do I need to take it back to my doc and have it re-worded? I have missed a few days, and have had to go home after half of my shift that I'm being penalized for under my FMLA.

Please help.

Shelia