No, I did not try to create a new online account. Actually, somehow I was able to access my old account after spending considerable amount of time and doing some tricky things. Sorry, I don't remember now how exactly I was able to re-gain access to my old account. The thing was that we used that account to monitor AOS cases for two different applicants (me and my wife). USCIS's recommendation now is to not mix cases of different applicants using the same account. At least, that was the case in August when we filed our N-400 apps. That is why we decided to get new accounts, one for myself, and one for my wife.
We were planning to file our naturalization papers by mailing them anyway because we had some complicating things related to continuous residence requirements. We attached a lot of evidence. It took about three days for papers to be delivered to USCIS lockbox and get accepted. The timer starts from the day USCIS accepts the application. Then it took about five days for USCIS to charge our credit card and issue receipt letter and biometrics reuse letter. So it's only about 3-4 days difference between filing online and mailing an application. Not much in larger scheme of things. Actually, gaining access to your account may take longer, if you wait for USCIS's help in doing it.
If you don't have to mail the application, the most efficient option is what OldUser said. Just try to open a new online account and file online. Should be fine to have two accounts.
Edit: I used different email for my second account.