If you're having problems with their multifactor really the only option is authenticating from a browser already logged in or using the backup codes...
what do you mean Firefox doesn't agree with your computer? You sounded like you didn't like Googled based (chromium). It's now either that or Firefox...
I'd say try again. Otherwise I don't know. I'd run all the test but at least the smart test and the long generic test. I don't know what the acoustic...