RecyclerView checks wrong items as i scroll down

I decided to use RecyclerView to display my list of data. There's a checkbox, 2 TextViews and one ImageView in each item/row. I have created my Adapter to handle everything, and to add the checked items to my final list.

The problem is that when I check a few items and scroll down some of the items will appear as checked and when I scroll up the ones I had checked previously appears as unchecked. The Images and the Textviews are OK, but the checkbox messes up when scrolling down and up.

This is my Adapter:

public class TeamAdapter extends RecyclerView.Adapter<TeamAdapter.MyViewHolder> {

    private Context mContext;
    private List<UserProject> UserList;
    private UserProject user;


    public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        public TextView name, description;
        public CircleImageView profile_image;
        public CheckBox check;

        public MyViewHolder(View view) {
            super(view);
            name = (TextView) view.findViewById(R.id.name);
            description = (TextView) view.findViewById(R.id.description);
            profile_image = (CircleImageView) view.findViewById(R.id.profile_image);
            check = (CheckBox) view.findViewById(R.id.check);
        }
        @Override
        public void onClick(View v) {
            if (mItemClickListener != null) {
                mItemClickListener.onItemClickListener(v, getAdapterPosition());
            }
        }
    }


    public TeamAdapter(Context mContext, List<UserProject> userList) {
        this.mContext = mContext;
        this.UserList = userList;

    }
    @Override
    public TeamAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.adapter_teams, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final TeamAdapter.MyViewHolder holder, final int position) {

        user = UserList.get(position);

        holder.name.setText(user.getName());
        holder.description.setText(user.getCompany());

        if(user.getImageURL() != null && !user.getImageURL().isEmpty()) {
            Picasso.with(mContext).load(user.getImageURL()).into(holder.profile_image);
        }

        holder.check.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    ActivityTeams.newList.add(UserList.get(position));
                }else {
                    ActivityTeams.newList.remove(UserList.get(position));
                }
            }
        });

    }


    @Override
    public int getItemCount() {
        return UserList.size();
    }

    private TeamAdapter.onRecyclerViewItemClickListener mItemClickListener;

    public void setOnItemClickListener(TeamAdapter.onRecyclerViewItemClickListener mItemClickListener) {
        this.mItemClickListener = mItemClickListener;
    }

    public interface onRecyclerViewItemClickListener {
        void onItemClickListener(View view, int position);
    }
}