Welcome aboard to the Community, mcs-tradecloud-s.
Let me help you with your goal to know why there are no invoices from August and onwards in your account.
We can use the Magnifying glass to search for the recent invoices you just created. Here's how:
Click the Magnifying Glass.
Enter the invoice number.
Should the transaction not appear, click Advanced Search.
Apply filters to narrow the search.
Feel free to check this article for additional information about this tool and other ways to locate transactions, check out the following article. It also contains detailed steps and different options: Search for transactions.
If you're still unable to locate the transaction or suspect that it may have been removed, I recommend searching the Audit Log. This tool shows changes that are made within an account.