After a budget begins receiving responses it becomes LIVE and the Edits that you can make are limited.
If the budget hasn't received any responses, you can fully edit the budget.
If a budget has received responses (including test responses before going live) you cannot delete it.
If a budget has received responses (including test responses before going live) you cannot change the total budget amount.
In order to delete a LIVE budget, you must first delete the responses at the bottom of the View Budget screen
From here you can view each Budget Response and then delete each response using the Delete Budget Response button in the top right corner