Hello Anja!
BetterMe is a subscription-based service, and all the subscription details, including the warning about the auto-renewal, are stated before and after the purchase.

Please email us at trust@betterme.world, or send us a 7 or 8-digit ID number from the auto-reply here. We would gladly assist you with your request and work towards finding a solution. 
We encourage you to get in touch, as we deeply value your input and treat it with the utmost seriousness.

Looking forward to your reply.
Kind regards, Team BetterMe.