How to get only checked checkboxes in codeigniter

I Have multicheckbox with input fields, where im inserting them into my database, but theres if i didint check and fill all inputs im not reciving values of that checked checkboxes

this is my view of checkboxes:

                        <!-- Form Name -->
                    <legend>Изберете типове за имота</legend>

                    <!-- Multiple Checkboxes (inline) -->
                    <div class="form-group">
                      <div class="col-md-4">
                        <label class="checkbox-inline" for="checkboxes-0">
                          <input type="checkbox" name="data[1][property_type_id]" id="checkboxes-0" value="22">
                          Пентхаус
                        </label>
                          <br>
                    <!-- Text input-->
                    <div class="form-group">
                      <div class="col-md-8">
                      <input id="cena" name="data[1][alt_txt]" type="text" placeholder="Въведи цена" class="form-control input-md">

                      </div>
                    </div>

                        <label class="checkbox-inline" for="checkboxes-1">
                          <input type="checkbox" name="data[2][property_type_id]" id="checkboxes-1" value="21">
                          Гараж/Паркомясто
                        </label>
                    <br>
                                            <!-- Text input-->
                    <div class="form-group">
                      <div class="col-md-8">
                      <input id="cena" name="data[2][alt_txt]" type="text" placeholder="Въведи цена" class="form-control input-md">

                      </div>
                    </div>

                        <label class="checkbox-inline" for="checkboxes-2">
                          <input type="checkbox" name="data[3][property_type_id]" id="checkboxes-2" value="20">
                          Бизнес
                        </label>
                        <br>
                    <div class="form-group">
                      <div class="col-md-8">
                      <input id="cena" name="data[3][alt_txt]" type="text" placeholder="Въведи цена" class="form-control input-md">

                      </div>
                    </div>

and this is my model where im inserting my checkboxes into table:

        public function save_dynamic($data, $id)
    {
        // Delete all
        $this->db->where('property_id', $id);
        $this->db->where('value !=', 'SKIP_ON_EMPTY');
        $this->db->delete('property_value'); 

        // Insert all
        $insert_batch = array();
// Process the POST DATA from the FORM        
        foreach($data as $key=>$value)
        {
// Do this if the key is called option
            if(substr($key, 0, 6) == 'option')
            {
                $pos = strpos($key, '_');
                $option_id = substr($key, 6, $pos-6);
                $language_id = substr($key, $pos+1);

                $val_numeric = NULL;
                if( is_numeric($value) )
                {
                    $val_numeric = intval($value);
                }

                $insert_arr = array('language_id' => $language_id,
                                    'property_id' => $id,
                                    'option_id' => $option_id,
                                    'value' => $value,
                                    'value_num' => $val_numeric);

                if($value != 'SKIP_ON_EMPTY')
                    $insert_batch[] = $insert_arr;
           }
        }
        $data=$this->input->post('data'); 
        if(count($insert_batch) > 0) {
            $this->db->insert_batch('property_value', $insert_batch); 
        }

// We need to loop through each entry and add in the property_id    

        $insert_array = array();
        $property_id = array('property_id'=>$id);
        foreach($data as $array){
          $insert_array[] = array_merge($array,$property_id);
        }    
        if($this->db->affected_rows() > 0) {
            $this->db->insert_batch('property_type_details', $insert_array); 
            echo $this->db->last_query();
        }

my array looks like

    array(20) {
  [0]=>
  array(3) {
    ["property_type_id"]=>
    string(2) "22"
    ["alt_txt"]=>
    string(5) "25.22"
    ["property_id"]=>
    int(182)
  }
  [1]=>
  array(3) {
    ["property_type_id"]=>
    string(2) "21"
    ["alt_txt"]=>
    string(5) "30.10"
    ["property_id"]=>
    int(182)
  }
  [2]=>
  array(3) {
    ["property_type_id"]=>
    string(2) "20"
    ["alt_txt"]=>
    string(2) "25"
    ["property_id"]=>
    int(182)
  }

and this is what im getting if i didnt fill and check any checkbox

INSERT INTO `property_type_details` () VALUES ('25.22',183,'22'), ('30.10',183,'21')