I'm sorry to hear about the difficulties you are experiencing. I am not aware of any current technical issues that would explain the behavior that you are encountering when trying to schedule and save your listings.
I was able to access my own account, create a new listing and successfully schedule it without encountering the behavior that you are describing. I am using the latest version of the Firefox browser too. I'm sure that you have heard this before, but I recommend clearing your Internet browsers cache which includes closing and then reopening your Internet browser. Once you have done this, please try scheduling your listing once more. If you have already done this and you are still encountering this behavior, then please file a support case via the "Help" tab, then clicking the “File a Support Request” button on the ensuing page in your account, provide us with the Internet browser that you are using along with the version of said browser and we can investigate further.