This is my case,

I don't use invoices or bills, just customer payments.

Consider I've got an incoming payment from customer of 100$

after some time, I've refunded the 100$ back to customer as an outgoing payment.

Now the issue is when making a new invoice, even if we refunded 100$ back to the customer, the amount is still available to add to invoice as outstanding debit.

So how can I match and reconcile both payments of 100$ in this case?