I have a webhook that sends out an email to new customers based on invoice.paid whenever a new customer signs up.

I also have an email that goes out when customers update their payment method, using customer.updated.

Now, since a new customer sign-up also tiggers the customer.updated event, I have to filter somehow that the ‘payment method change’ email only goes out to existing customers. I do this by checking for a previous payment method.

Here is how I’m trying to do this, but the payment method email is still triggered by every new customer. Why?

Is there a better way to trigger the ‘payment method change’ email only for existing customers?

case 'customer.updated':

    $customer = $event->data->object;
    $customerId = $customer->id;
    $previousAttributes = $event->data->previous_attributes;

    // Check if invoice_settings.default_payment_method OR default_source has changed
    $newDefaultPaymentMethodId = $customer->invoice_settings->default_payment_method ?? null;
    $newDefaultSourceId = $customer->default_source ?? null;

    // Check if there was a previous default payment method or source
    $hadPreviousPaymentMethod = isset($previousAttributes['invoice_settings']['default_payment_method']) || isset($previousAttributes['default_source']);
    
    // Only proceed if there was a previous payment method or source
    if ($hadPreviousPaymentMethod) {
        $oldDefaultPaymentMethodId = $previousAttributes['invoice_settings']['default_payment_method'] ?? null;
        $oldDefaultSourceId = $previousAttributes['default_source'] ?? null;
        

        if ($newDefaultPaymentMethodId !== $oldDefaultPaymentMethodId || $newDefaultSourceId !== $oldDefaultSourceId) {

            // Retrieve the new default payment method or source details
            $paymentMethodId = $newDefaultPaymentMethodId ?: $newDefaultSourceId;
            try {
                $paymentMethod = StripePaymentMethod::retrieve($paymentMethodId);
                $paymentMethodType = $paymentMethod->type;
                $brand = '';
                $last4 = '';
                $exp_month = '';
                $exp_year = '';

                // Handle card payment method
                if ($paymentMethodType === 'card') {
                    $last4 = $paymentMethod->card->last4;
                    $exp_month = sprintf("%02d", $paymentMethod->card->exp_month);
                    $exp_year = $paymentMethod->card->exp_year;
                    $brand = ucwords($paymentMethod->card->brand);
                }
                // Handle LINK payment method (or any other)
                elseif ($paymentMethodType === 'link') {
                    $brand = 'LINK account';
                }
                // You can add more conditions for other payment types here

            } catch (StripeExceptionApiErrorException $e) {
                logError('Error retrieving payment method.' . $e->getMessage());
            }


            // Notify user
            SEND EMAIL
            }    
        }

  break;