Is this from Spain?

It sounds like what they are doing is clearly illegal and you probably could do a lot of people a favor by complaining to the authorities.

Generally for the eu: europarl.europa.eu/…/E-8-2017-003934-ASW_EN.html “If users receive unsolicited communications after having withdrawn consent, they can file a complaint with the national regulatory authority. In addition, they have the right to a judicial remedy before national courts.”

The responsible agency for Spain: www.aepd.es