How to insert pivot table in case of many to many relation? (Laravel 5.3)

My form to add data is like this :

When klik save, It will call controller

My controller is like this :

public function store(Request $request)
{
    $param = $request->only('account_name','account_number','bank_id','branch');
    $result = $this->user_service->addUserBank($param);

    if($result)
        $status='success';
    else
        $status = 'failed';
    return redirect('member/profile/setting/account')->with('status',$status);
}

My service is like this :

public function addUserBank($param)
{
    $instance = User::where('id', '=', auth()->user()->id)->first();
    $param['user_id'] = auth()->user()->id;
    $param['status'] = 0;
    $instance->banks()->attach([
                'status' => $param['status'], 
                'account_name' => $param['account_name'],
                'account_number' => $param['account_number'],
                'branch' => $param['branch']
            ]);
    return $result;
}

My model user is like this :

<?php
namespace App;
use App\Models\MasterData;
use Collective\Html\Eloquent\FormAccessible;
use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;
class User extends Authenticatable
{
    use Notifiable, FormAccessible;
    protected $fillable = [
        'name', 'email', 'password', 'api_token','birth_date','mobile_number','gender','full_name'
    ];
    protected $hidden = [
        'password', 'remember_token',
    ];
    public function banks()
    {
        return $this->belongsToMany(MasterData::class, 'users_banks', 'user_id', 'bank_id')  ->withPivot('status','account_name','account_number','branch')->withTimestamps();
    }
}

So I have 3 table : users table, users_banks table (pivot table), and master_datas table

List of the names of the banks located in the master_datas table with type bank

Users table have field id, name, email, password etc => See model user

Master_datas table have field id (this is bank id), name (this is bank name), type (there exist type of bank, order status etc. So, get type = bank)

Users_banks table have field id, user_id, bank_id, status, account_name, account_number, branch

When run, it does not successfully insert into the pivot table (table users_banks).

It looks like my way to insert into the pivot table, not true.

Can you help me?

Additional

Table Master_datas is like this :