You will need to create this person as a supplier and then as a customer.
If this person as a customer owes you $5,000 and you owe this person as a supplier $3,000, what you want to do is to offset $3,000 from both amounts so you don’t owe anything while they still owe you $2,000.
You can enter this non-cash offset transaction as a journal entry where you record it as:
- Account:
Customer credits, credit $3,000 - Account:
Supplier credits, debit $3,000
Maybe in future it will be possible to link related customer & supplier accounts so these entries would be done automatically.