Since it's tedious as fuck to find copy-pasteable email templates to throw at people sending batches of unsolicited marketing garbage, because all the results in web search engines are all about creatively interpreting the GDPR to actually send spam, here is mine:
Since I'm an European Union citizen, all my personal data, including my email address, are protected by the Data protection Regulation (GDPR), even if your company is based outside of the EU. See https://www.privacy-regulation.eu/en/ for details.
As a data controller you are thus subjected to various obligations, notably transparency.
As per Article 15 ( https://www.privacy-regulation.eu/en/15.htm ), please do provide me with: 1. all the personal data you have about me; 2. the purpose of the processing; 3. why and how you collect/got access to them; 4. if you share my data with other entities.
As per Article 7, ( https://www.privacy-regulation.eu/en/7.htm ), if this processing is based on my consent, please do send me the information demonstrating that I have indeed consented to it.
As per Article 17, ( https://www.privacy-regulation.eu/en/17.htm ), I also want all my personal data to be destroyed from your databases or other storage. But only after you provide me with the information requested above.
As per Article 19, ( https://www.privacy-regulation.eu/en/19.htm ), do ask any company to whom you might have transferred my data to do so as well, and provide me with proof of said destructions.
As per Article 12 (3) ( https://www.privacy-regulation.eu/en/12.htm ), you have one month to fulfill this request. After said period, be assured that I will refer the case to the competent supervisory authority ( https://edpb.europa.eu/about-edpb/board/members_en ), that has power to hand out significative fines ( https://www.privacy-regulation.eu/en/83.htm ).
Have a nice day,