2Birds - I figured out how to get the alternative code. But it doens't work for me. So you need the lastpass browser extension installed. You open the browser extension, click forgot password, then click account recovery options. You will then be prompted to enter your email and then a code will be sent to you. BUT this will only work if you logged in through the browser extension at any point in the past on that computer. So you have to use the same computer that has the browser extension that you previously logged into in the past. If you never logged in this way - you are still screwed - like me.
So if you can't find the browser extension, my guess is that you never had it installed either. Which means you can't get the alternative code. In order to receive the alternative code, you would have had to previously install the extension and successfully log in through it.