When attempting to edit or delete an Offline Payment/Refund, first check if the record has been:
synced to QuickBooks Online (you can view this in Goodshuffle Pro)
and Deposited into your bank (you can view deposits for offline payments in Quickbooks Online)
You can view if a payment was synced with QBO by clicking the "Plus" icon to the left of the payment and viewing the last QuickBooks Sync date. In the below example we're viewing an Offline payment.
If it has been synced you'll first need to remove this payment or refund from the connected Deposit in QuickBooks Online before editing/deleting it in Goodshuffle Pro.
Click the blue link arrow next to the "Quickbooks Sync" on the payment or refund - this will open up this payment in QuickBooks Online in a new tab.
When viewing the payment/refund in QuickBooks Online, if it was deposited, you can see the date of the deposit in the top left.
Click that date, and you'll want to deselect (or 'uncheck') the matching payment or refund connected with a particular deposit.
Once cleared, you'll be able to edit/delete the transaction in Goodshuffle Pro!
If you're still encountering issues, you'll need to 'Unmatch' the Deposit with the transaction record from your bank, then delete the Deposit within QuickBooks Online. You can learn more about undoing a Matched Deposit here (Article).