First off, it is too late now but you should NOT have signed anything under duress. Since you did though, you might consider talking to someone in the upper levels of Whole Foods to explain your position and how you were treated.
If you were not allowed to leave until you signed the forms and were not charged or detained by law enforcement that is a huge problem and I think you need to report that! Were the police called? You need to find out if any police reports were filed and you need to have copies of what you signed.