I am trying to get multiple inputs from a dropdown list but its returning a no value.

Here is my code:

controller:

public function mark_error($id = null, $email = null)
{
    if ($this->userlib->isLoggedIn())
    {
        if ($this->userlib->isAdmin())
        {
            $seller_error = $this->input->post('seller_error');
            if (is_null($seller_error))
            {
                $seller_error = array();
            }
            $marked_error_seller = implode(',', $seller_error);

            $bank_error = $this->input->post('bank_error');
            if (is_null($bank_error))
            {
                $bank_error = array();
            }
            $marked_error_bank = implode(',', $bank_error);

            $store_error = $this->input->post('store_error');
            if(is_null($store_error))
            {
                $store_error = array();
            }
            $marked_error_store = implode(',', $store_error);

            $id2 = $this->userlib->getId();
            $data['admin_data'] = $this->admin_panel_model->admin_data($id2);

            $data['marked_error_seller'] = $marked_error_seller;
            $data['marked_error_store'] = $marked_error_store;
            $data['marked_error_bank'] = $marked_error_bank;
            $data['email'] = $email;

            $this->admin_panel_model->mark_error_seller($id, $marked_error_seller);
            $this->admin_panel_model->mark_error_bank($id, $marked_error_bank);
            $this->admin_panel_model->mark_error_store($id, $marked_error_store);                               
            $this->load->view('send_mail', $data);
        } else {
            echo "User not Allowed";
        }
    } else {
        echo "User not Logged In";
    }
}

model:

public function mark_error_seller($id, $marked_error_seller)
{
    $data = array('marked_error_seller' => $marked_error_seller, 'seller_status' => 2);
    $this->db->update($this->seller_table, $data, array('id' => $id));
    $status = array('error_status' => 1, 'admin_check' => 8);
    $this->db->update($this->table, $status, array('id' => $id));
}

public function mark_error_bank($id, $marked_error_bank)
{
    $data1 = array('marked_error_bank' => $marked_error_bank, 'bank_status' => 2);
    $this->db->update($this->bank_table, $data1, array('id' => $id));
    $status = array('error_status' => 1, 'admin_check' => 8);
    $this->db->update($this->table, $status, array('id' => $id));   
}

public function mark_error_store($id, $marked_error_store)
{
    $data2 = array('marked_error_store'=>$marked_error_store, 'store_status' => 2);
    $this->db->update($this->store_table, $data2, array('id' => $id));
    $status = array('error_status' => 1, 'admin_check' => 8);
    $this->db->update($this->table, $status, array('id' => $id));
}

view:

 

                          

                            Seller Details
                            
                                    Business Name
                                    Business Address
                                    Mobile
                                    City
                                    State
                                    Pincode
                                    PAN
                                    PAN Proof
                                    TAN
                                    TIN
                                    TIN Proof
                                    STRN
                                    STRN Proof
                                    Residence Address
                                
                                Bank Details
                                
                                    Beneficiary Name
                                    Bank Account Number
                                    IFSC Code
                                    MICR Number
                                    Bank Name
                                    City
                                    Branch
                                    Cancelled Cheque
                                    Address Proof
                                    Type of Address Proof
                                    Identity Proof
                                    Type of Identity Proof
                                    
                                
                                Store Details
                                
                                    Billboard Image
                                    Company Display Name
                                    Company Description
                                    Company Logo
                                    Travel Category
                                    Travel Sub Category
                                    Travel Region
                                    
                                
                          
                          
                          

                        
                            
                          
                        

To elaborate,the status is successfully changed in the database, but the inputs from the three dropdown list are not being updated.