Automated telephone call about sending spam mails

That is not a normal way to report spam. In fact, it's utterly bizarre.

The generally accepted way to report spam is through the abuse@ email contact of the owner of the IP address which sent the email to you. In the case of email you sent through a firm in Berlin, such email would be directed either to them, or to their Internet service provider or datacenter from which they sent the mail. You would not see it until the firm forwarded it to you for appropriate action (e.g. unsubscribing the user).

The other common way spam gets reported is through email feedback loops from large email service providers (e.g. Gmail, Yahoo, Hotmail, Yandex, etc.). When a user clicks the Spam/Junk button in these services, a report is generated. You would have had to opt in to receive these, and you would generally also get them delivered by email.

In the old days, before abuse@ was a standardized thing, and before spam was a serious problem, we might pick up the phone and call the phone number listed in the whois record, but (1) it would be a human being calling, not an automated recording, and (2) that hasn't really been done since the late 1990s except for extremely unusual situations. And we'd end up having to forward a copy of the email anyway.

I have no idea why you received an automated call, but if they weren't willing to send an email in the usual way, and weren't willing to have a human being talk to you, then I don't see why you should be expected to waste any time on it.

Definitely not a common way to respond. I'd likely just ignore it, if it weren't easy to validate.