Not able to reload data properly when retrieving objects from Parse

I am retrieving data from "_User" class this way:

my declarations ..

 var userIds = [userListTableViewCell]()
 var userNames = [String]()
 var profilePics = [PFFile]()
 var gender = [String]()


var userQuery = PFUser.query()
        userQuery?.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in

            if let objects = objects {

                self.userIds.removeAll(keepCapacity: true)
                self.userNames.removeAll(keepCapacity: true)
                self.profilePics.removeAll(keepCapacity: true)

                for object in objects {

                    if let user = object as? PFUser {
                        if user.objectId != PFUser.currentUser()?.objectId {

                            self.userIds.append(object["objectId"] as! userListTableViewCell)  // getting an error here..  "unexpectedly found nil while unwrapping an Optional value"
                            self.userNames.append(object["fullName"] as! String!)
                            self.profilePics.append(object["profilePicture"] as! PFFile!)
                            self.gender.append(object["gender"] as! String!)

                        }


                    }
                    self.tableView.reloadData()
                }


            }




        })

]1

here when i click on follow button for user "Rfdfbd" then automatically the "unfollow" title appears on user "Ihbj....." also :/ how can i fix this??

my IBAction followButton code is here:

@IBAction func followButtonTapped(sender: UIButton) {

    println(sender.tag)

    sender.setTitle("unfollow", forState: UIControlState.Normal)

    let getOjbectByIdQuery = PFUser.query()
    getOjbectByIdQuery!.whereKey("objectId", equalTo: userIds[sender.tag])
    getOjbectByIdQuery!.getFirstObjectInBackgroundWithBlock { (foundObject: PFObject?, error: NSError?) -> Void in

        if let object = foundObject {

            var followers:PFObject = PFObject(className: "Followers")
            followers["user"] = object
            followers["follower"] = PFUser.currentUser()
            followers.saveEventually()

        }
    }
}

I am using sender.tag for the follow button here..