UNABLE TO EDIT OR CHANGE MY PRIVACY SETTINGS

Hi there<br> i am not sure who can assist me but as usual each member has people which they have blocked from their profile. now my problem is i by mistake blocked someone and now i need to unblock them but the privacy settings is not helping at all, i click and nothing happens. I have sent a request via the help option on fb a few times now and still nothing. Please can someone assist me asap