Let me share some information to make sure that you receive payment-related notifications.
You'd want to make sure that your payment notification email delivery is set in the Account and Settings page within QuickBooks.
If your email address is entered correctly, you'd want to make sure that your email is configured properly. Let's access your email and review your Spam and Junk folders to see if these notification are being routed to the wrong folder when they reach you. You can read through this article for more detailed steps: Unable to receive Intuit email.
Lastly, I'd recommend contacting our Payments Support team. They have the tools to securely look up your account and verify the payment transactions and chargebacks in your account.
Get back to us here if you have other questions about managing your customer's rejected bank transfer or payments. I'm always here to lend a hand.