Thanks for updating us on this @BossLadyJatGHA, and following the steps provided by my peer above. There might be some confusion in recording transactions that may have caused the total to be inflated. Don't worry, I can help you sort this out.

Creating a check to record the $800 will not increase the income but will correct your bank and Accounts Receivable balance. However, recording the repayment received, determines why the income account was overstated with the same amount of $800. To rectify this, I recommend deleting the repayment.

Once done, create a receive payment first for the recorded check amount. Make sure to put a checkmark on the amount due. I'll guide you on how:
 

1. Go to the Customers menu.
2. Select Receive Payments.
3. Tick the amount due.
   
   
    
4. Then Click Save & Close.

Then, create a Bank Deposit and include the repayment. Here's how:
 

1. Go to the Banking menu, then select Make Deposits.
2. Select the repayment from the Payments to Deposit window, then click OK.
   
   
    
3. Once done, select Save & Close.

That should do it. You can also reconcile your account to check for any discrepancies.

Moreover, I'm adding this helpful article to learn the different ways you can track customer transactions in QuickBooks Desktop: Get started with customer transaction workflows.

Let me know if you have additional clarifications or concerns. I'll be around to lend a hand.