You can pause and delete the recurring invoice so that it will not create a new invoice transaction every month. I'd be happy to show you the steps on how to stop it. Refer to the steps below:
Go to the Settings and select Recurring transactions under the Lists column.
Locate the invoice transaction, click the drop-down button beside it, and select Pause.
Select the drop-down button again and click Delete.
I've also added some screenshots for your additional reference: