Disconnecting your Monzo account from QuickBooks
Before disconnecting your account, make sure you match or delete all of the downloaded transactions on your account. QuickBooks won’t let you make changes if there are still pending transactions.
From your QuickBooks Online account, tap on the Banking tab
Select the bank account you want to disconnect, then tap on the pencil icon in the top right corner and tap Edit Account Info
Select Disconnect this account on save and tap Save
Your Monzo account's now disconnected from QuickBooks.