You will need to reset your master password but good luck with that. I don't know what happened to LastPass Support but apparently the whole department has been laid to waste, as has their Product Development.
I have biosecurity on the mobile app thank god but can't get into the vault via the web or the browser extension so I can't export everything. If I don't get help soon I'm just going to consider it a lost cause and reset passwords as I go and use a different storage option.
I'm a Premium user and the fact that I have to log in, with my master password that I don't have, to get to Premium support is just...
So sorry - no real help for you other than to start over with a new account. Or switch to Bitwarden (CNET's current top pick).