Had a customer pay $1400 in cash for $1380 of services. They needed me to obviously give them $20 back. $20 needs to come from CoH and I’m adding 1380 how is this done.

Pleased to guide you on how to record the refund, justin-flywellav.  

We can directly deposit the whole $1400.00 then create a check or expense to reduces your bank's balance and zero out the customer's overpayment. You can refer to this link in creating a deposit: Record and make deposit. 

Once done, we'll have to record the refund for your customer:

1. Click the + New icon, and choose Check or Expense.
2. Drop-down arrow from the Payee, and select the customer you want to refund.
3. Drop-down arrow from the Payment account, pick the bank account where you deposited the over-payment.
4. From the Payment method drop-down, select Cash.
5. In the Category column, select Accounts Receivable.
6. Enter $20 in the Amount field.
7. Press Save and close. 

Then, let's link the refund to the customer's over-payment:

1. Click the + New icon, and select Receive payments.
2. Select the same customer you used for the check or expense.
3. Enter the necessary information needed.
4. Under the Outstanding Transaction section, mark-check the box for the expense or check you created.
5. Hit Save and close to complete the process. 

I have this handy article to learn, and will guide you in recording a refund for goods or services: Record a customer refund. 

If you want to trace the refund receipts that you've processed for the year, you can pull up the Transaction List by Customer report to show all the refunds. 

That should do it. If you need any further information or assistance with managing your refunds in QuickBooks, please don't hesitate to leave a comment below. I'm always happy to help. Have a great day!