I have some idea on how to retrieve your customer data. Sometimes, the unexpected behavior of QBO is browser-related. Let's access your account via a private browser to isolate the case. This browsing doesn’t store data and will help the page load without issues from temporary data.
Press CTRL+SHIFT+N for Chrome.
Hold CTRL+SHIFT+P for Firefox.
Press Command + Shift + N (Safari).
After that, go back to your customer profile. If it's working fine, it's a good idea clear the cache to start on a clean slate. This process helps the browser to fetch the latest version of the webpage and faster browsing experience.
If you're getting the same result, please contact our Customer Care Support so we can investigate further. You can use this link to reach out: QuickBooks Online Support.
In case you need help with other customer tasks, click this link to go to our general topic with articles.
Feel welcome to message me anytime if you still have questions or concerns. I'll be around for you. Take care and have a good one.