Thanks for posting here in the Community. I'd be pleased to provide you with some details about why your income is not showing on your Profit and Loss.
When pulling up Profit and Loss report in QuickBooks Desktop, you'll need to check your accounting basis (cash/accrual) for some times it may cause other transactions not to show. Once verified, you need to make sure that your Point of Sale is synced properly to your QuickBooks.
If the transactions were synced and still not showing on your P&L report, then you'll need to reach out to our POS support to check on the mapping of your transactions. You can reach them through the contact details found in this link: QuickBooks Point of Sale.
Also, here's an article that you can check out about the financial exchange with POS for your future reference: Financial Exchange Overview.
That should do it!
Please know that I'm just a post away should you need anything else concerning QuickBooks. I'll be around to help you out. Wishing you a wonderful day ahead.