Greetings, @Find.
Welcome to the Community. I want to help you with the chargeback from the customer's bank.
You need to submit the required documents to resolve disputed chargebacks from a customer. The time frame of the process can take up to 60 days depending on the card issuing bank.
If you haven't submitted the requirements yet, you can check this article (scroll down to What documents do you need to respond to a chargeback, retrieval or inquiry?):
Chargeback FAQs.
You can also check other faqs provided in the article for more information about how to resolve the problem.
To fix this as quickly as possible, please reach out to our Phone Support Specialists. They'll be able to review your documents and help check it on their end.
Please reach them through this article:
Get help with QuickBooks Online.
Feel free to let me know if you have any questions or you need further assistance. The Community is always here for you.