Immediately (30') after I got the first e-mail saying that my account was deleted, I replied to the operator and told her I just wanted to opt-out, not having my account deleted. She replied quickly (another 30'), said that she was sorry for the misunderstanding, and reinstated my account.

Sidenote: Apparently my opting-out request got redirected to another operator who should have got in contact with me, but 17 days after I am still waiting.