How to know when Shopify debits our bank account for refunds?

[Tom_Field]

We have exported a  Shopify Payments report (Under  Analytics, Reports, Payments).

The Gross Payment column minus the Refund column = the Shopify 1099 "Gross amount" field.

So on our 1040 tax return, we will use the above report's total Refund amount as an expense against the gross 1040 amount. 

Except... if our payout account lacks sufficient funds for the refund, Shopify online help says, "the refund will be debited from your bank account."  (https://help.shopify.com/en/manual/payments/shopify-payments/getting-paid-with-shopify-payments/refu...) 

How can we determine when that happens?   Is there a report that shows the dates and amounts of those debits to our checking account? 

Are there other times Shopify debits our bank account, or can we assume all bank account debits from Shopify are for refunds?

Also, are there other store expenses that Shopify deducts from Payouts rather than billing us on our credit card?

At what point in the accounting process does Shopify deduct credit card fees?