BraintreeService.php

public function removePaymentMethod( PaymentMethod $paymentMethod, User $user ) {

        $token = $paymentMethod->token;

        $BTPaymentMethod = $this->gateway->paymentMethod()->find($token);

        $isDefault = $BTPaymentMethod->isDefault();

        $result = $this->gateway->paymentMethod()->delete($token);
        // dd($result);
        if ( $result->success ) {
            // run some executions.

            $paymentMethod->delete();


            // assign new default card.

            $paymentMethodNew = $user->paymentMethods()->latest()->first();

            if( $isDefault ) {
                if ( $paymentMethodNew ) {
                    $result = $this->gateway->customer()->update($user->braintree_id, [
                        'defaultPaymentMethodToken' => $paymentMethodNew->token
                    ]);

                    $paymentMethodNew->update([
                        'default' => true
                    ]);
                }
            }

        } else {
            // notify admin.
            abort(500);
        }

        return;
    }