If you created your Flipd account under an email address and would like to change it, please follow these steps:
Log out of your current account. Take note of which email address it's under.
Create a new account under a different email address.
Contact email@example.com with your old account email address & your new account email address.
Request that any data be transferred from your old account to your new one.
Log back into your old account and delete it (Settings > Manage Account > Delete).
Your email address is private and cannot be seen by other users on the app.
If your email address is showing "...@privaterelay.appleid.com" that just means that you opted to hide your Apple ID email address from Flipd. Any communications from Flipd will be forwarded to your email address connected to your Apple ID, but it will not know what that email address is.