Hi Florian

Thank you for reaching out to us.

Unfortunately, Amelia doesn't have an "Unsubscribe" button, so this would have to be developed as a custom solution (included support for the plugin doesn't cover that).

The only solution at this time would be to add a short description to your emails, that would instruct your customers to log into the panel, and delete their profile.

That would delete the customer from Amelia's database, and they'd no longer be listed as customers, nor would they receive emails from you.

You are most welcome

My apologies if I already asked this before, but may I ask you for a small favor if you don’t mind? 

Can you, please, leave a review on the Lite version of Amelia if you have an account at wordpress.org and have a couple of minutes? No need to write any specific text. And cast a vote on 

https://www.templatemonster.com/awards/category/booking-appointment/

It’d mean a lot to us, and as a token of our appreciation, we would like to offer you a $10 credit for SMS notifications.

Thanks in advance.