I see you are dealing with issues regarding your recorded expenses and suppliers in QuickBooks Online (QBO). Let’s address your questions individually to help you resolve these issues effectively, Britannia.
First, we can use the filter option to select the date range for the purchase order you want to view. I've added a screenshot for your reference.
Second, transactions are categorized as split when multiple accounts or categories are used within a single transaction.
Third, we can open the transactions and manually change the supplier. If these transactions have different suppliers, then they should also have different transactions.
Lastly, we can go to the Expenses list to review the transactions and manually delete them if necessary.
Furthermore, I'm adding this article for your guidance in sending a purchase order: Create and send purchase orders in QuickBooks Online.
I'm always prepared if you have questions or concerns about purchase orders. I'll be here to help. Keep safe!