Welcome to the Community, @HJL1. I’m here to ensure you’ll be able to reach out to Melio support so you’ll be able to sort out those issues with them.
While you can’t reach out to Melio via an online portal, email, Twitter, or phone, you might consider entering your concerns through the Melio help desk. This way, you’ll be able to find some possible fixes while you still haven’t heard from them yet.
I’ve also added this link that you can use to try getting in touch with them again. You can scroll down to the Contact section for further details: https://quickbooks.intuit.com/app/apps/appdetails/melio/en-us/.
Furthermore, you might also want to check out this article about paying your bills online within QBDT. This handy article will help you manage your cash flow: Pay bills online from QuickBooks Desktop.
Stay in touch if you have other questions or concerns about processing payments in QBO. I’ll be right here to answer them for you. Enjoy the rest of the day.