添加信用卡返回成功但没有CC保存：Braintree PHP API

I plan to update the default credit card through my system but I read here that it's not possible and that it should just be a newly created credit card. I'm following this documentation. I have 2 payment methods in my sandbox account.

Here's my code:

function create_cc($customer_id, $attributes){
    //Array ( [token] => j699th [cvv] => 222 [number] => 4005519200000004 [expirationMonth] => 12 [expirationYear] => 22 ) 

    $result = Braintree_Configuration::gateway()->paymentMethodNonce()->create($attributes['token']);

    return Braintree_Configuration::gateway()->paymentMethod()->create([
    'customerId' => $customer_id,
    'paymentMethodNonce' => $result->paymentMethodNonce->nonce,
    'cvv' => $attributes['cvv'],
    'number' => $attributes['number'],
    'expirationMonth' => $attributes['expirationMonth'],
    'expirationYear' => $attributes['expirationYear'],
    'options' => [
        'makeDefault' => true,
        'verifyCard' => true
      ]
    ]);

}

When the function above is called, it returns true so I'm expecting Payment Methods to be 3 in Braintree. But when I reload the page, I still get 2 payment methods. I made sure I have paymentMethodNonce' in my array data.

UPDATE:

Sandbox: It needs to be 'fake-valid-nonce' and not an actual one.

Production: not working.

Here's my code:

function create_cc($customer_id, $attributes){
    $nonce = '';
    if($this->environment == 'production'){
        $result = $this->gateway->paymentMethodNonce()->create($this->create_client_token());//$this->gateway->paymentMethodNonce()->create($this->create_client_token());
        $nonce = $result->paymentMethodNonce->nonce;
    } else if($this->environment == 'sandbox'){
        $nonce = 'fake-valid-nonce';
    }

    return $this->gateway->paymentMethod()->create([
    'customerId' => $customer_id,
    'paymentMethodNonce' => $nonce,
    //'cvv' => $attributes['cvv'],
    'number' => $attributes['number'],
    'expirationMonth' => $attributes['expirationMonth'],
    'expirationYear' => $attributes['expirationYear'],
    'options' => [
        'makeDefault' => true,
        'failOnDuplicatePaymentMethod' => true,
        //'verifyCard' => true
      ]
    ]);
}

What could I be doing wrong?