The payment received from couple of years back got automatically applied to the latest invoice raised. how can we find out why this happened?

Hi there, 

I see you've been with us for a long time now. We appreciate your loyalty! 

Don't worry, I'll be happy to give you a hand with showing you how to check your transaction history. The quickest way to view any transactions you've processed in QuickBooks is using the Audit log. You can see the changes made to your books and who made them using the audit log. It also tracks user login/logout activity, changes to settings, customers, suppliers, and employees. Since you're looking for what happened with the transactions, review the following steps for further instructions. 

Here are the steps on how to access the audit log:

1. Go to Settings ⚙ and select Audit Log.
2. Select Filter.
3. Use the fields on the Filter panel to choose the appropriate User, Date, or Events filter to narrow the results.
4. Select Apply.  

Give this a try and let me know how you make out. If you need further assistance with this, don't hesitate to contact our support team using this link here