Scope

Is there an identification/id to map the disputes to invoices?

How to identify the invoice related to the refund?

Chargebacks are directly handled by the payment gateway that you use (Eg: Stripe) and as a merchant, you would directly receive a notification from the gateway regarding these. 

If you have received Webhooks from Stripe for refund transactions, then search for    "balance_transaction": "txn_xxxxxxxxxxxxxx"

This is the transaction id present in Chargebee. 

Go to Chargebee site -> Logs -> Transaction and search for the specific transaction id. 

Open the transaction and click on invoice #. It will open the respective invoice. Follow these steps to ensure the refund is manually recorded for this specific invoice