How to cancel subscription when customer's credit card expires / insufficient fund? Laravel Cashier

I know this thing will be handled by the webhooks, so i have added

Route::post(
   'stripe/webhook',
   '\Laravel\Cashier\Http\Controllers\WebhookController@handleWebhook'
   );

Also Added in VerifyCsrfToken Middleware

protected $except = [
    'stripe/*',
];

Now i don't know what to do next. Can anyone please explain the next steps?

via Chebli Mohamed