Holy crap I did this this on accident when I tried signing up for an Alexa skill in the Alexa app and accidentally created a new account with same Amazon.com email address, then got flagged for suspicious activity cause I was on a VPN and got blacklisted. It took so many calls for customer support to acknowledge there was even an issue and they still told me to just use a different email in the end. I was passed and just made a new Amazon account with the original email address, but simply added a period in the middle and still use it while locked out of the other original account. It’s bonkers lol