Onscroll selected checkbox getting checked using listiview

In my application i added checkbox with ListView,and i also gave limitation for checkbox,user can not select more than 5 checkbox,but the issue is on scroll my selected checkbox get unchecked following is my snippet code,can any one help me with this

public class CustomAdapter extends BaseAdapter {

    private LayoutInflater inflater = null;
    Context context;

    String rup = "\u20B9";
    private ArrayList<ModelPooja> listData;
    boolean checked[];

    public CustomAdapterPooja(Context mainActivity, ArrayList<ModelPooja> listData) {
        // TODO Auto-generated constructor stub

        context = mainActivity;
        this.listData = listData;
        inflater = (LayoutInflater) context.
                getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        checked = new boolean[listData.size()];
        for (int i = 0; i < checked.length; i++) {
            checked[i] = listData.get(i).isselected;
        }

    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return listData.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }


    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
         final ViewHolder holder;

       if (convertView == null) {
        holder = new ViewHolder();
        convertView = inflater.inflate(R.layout.list_item_poojaselection, null);
        holder.tv = (TextView) convertView.findViewById(R.id.list_item_poojaname);
        holder.serviceprice = (TextView) convertView.findViewById(R.id.list_item_poojaprice);
        holder.dayss = (TextView) convertView.findViewById(R.id.list_item_poojadays);
        holder.txtseledates = (TextView) convertView.findViewById(R.id.selecteddatess);
        holder.checks = (CheckBox) convertView.findViewById(R.id.list_item_poojacheck);

       convertView.setTag(holder);

     }else {
           holder = (ViewHolder) convertView.getTag();
       }
        holder.checks.setOnCheckedChangeListener(null);
        holder.checks.setFocusable(false);

        holder.checks.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton cb, boolean b) {

                if (checkMaxLimit()) {
//
                    if (listData.get(position).isselected && b) {
                        holder.checks.setChecked(false);
                        listData.get(position).isselected = false;

                    } else {
                        holder.checks.setChecked(false);
                        listData.get(position).isselected = false;
                        Toast.makeText(context, "Max limit reached", Toast.LENGTH_SHORT).show();

                    }
                } else {
                    if (b) {
                        listData.get(position).isselected = true;
                    } else {
                        listData.get(position).isselected = false;
                    }
                }

            }
        });
        if (listData.get(position).isselected()) {
            holder.checks.setChecked(true);
        } else {
            holder.checks.setChecked(false);
        }

        holder.tv.setText(listData.get(position).getPOOJA_LISTING_NAME());
        holder.dayss.setText(listData.get(position).getPOOJA_LISTING_DAYS());
        holder.serviceprice.setText(rup + listData.get(position).getPOOJA_LISTING_AMOUNT());

        return convertView;
    }

    public boolean checkMaxLimit() {
        int countermax = 0;
        for (int i = 0; i < checked.length; i++) {
            checked[i] = false;
            checked[i] = listData.get(i).isselected();
            if (listData.get(i).isselected()) {
                countermax++;
            }
        }
        return countermax >= 5 ? true : false;
    }

    public class ViewHolder {
        TextView tv;
        TextView serviceprice;
        public CheckBox checks;
        public TextView dayss;
        public TextView txtseledates;
    }


}