Hi. Congratulations on having the highest number of attached devices we're seen so far... Once you get to this stage, your only option is to contact support. In normal circumstances this would not be a quick process. At this time of year after a new product release and in the middle of a pandemic...
Your viable options are:
Upgrade, if you can, on a monthly basis. You get better access (though still not quick) to support, you should immediately get access to your account so additional devices can be removed, and you can downgrade your account to Basic again as soon as this is sorted out.
Raise a support ticket with Evernote via Twitter @EvernoteHelps and carry on with a different email address and a new Basic account while the old one gets sorted.