How do I retrieve all my customers invoices and estimates as they all seem to have disappeared and I am up the creek without a paddle ?

This is unusual behavior, service-justinwi.

I'm here to ensure you'll be able to retrieve all your invoices and estimates.

Beforehand, may I know how the transactions became missing and the steps you performed before they disappeared? Adding additional details will help us provide accurate steps to resolve the issue.

In the meantime, I recommend logging out and logging back into QuickBooks Online (QBO). Doing so refreshes your account for the system updates to take effect. 

If this isn't the case, I suggest accessing your account using a private window. This way, we can determine whether this is a browser cache-related issue. The browser utilizes cached data to load web pages quickly. However, excessive cache can lead to problems that impact the appearance and functionality of your account.

An incognito mode helps us verify the issue since this doesn't save any files. Here are the keyboard shortcuts: 

• Safari: Command + Shift + N 
• Google Chrome: CTRL + Shift + N
• Mozilla Firefox or Microsoft Edge: CTRL + Shift + N

If the Manage users show, clear the browser's cache. Doing so deletes all the data from your browser and optimizes its performance. Using other supported browsers also helps us verify if this is a browser-specific issue. 

I'll be around if you need more help managing your sales transactions, service-justinwi. Please keep me in the loop by tagging me in your reply. Keep safe!