Ask HN: Anyone tried requesting personal data from their GSM provider via GDPR?

I'm thinking of doing that to see if they collect and if so how long do they store any of the following information:

  - Call history, including metadata and potentially also contents;
  - Text messages, same as with calls: metadata and potentially the contents;
  - Location history;
  - Data connection activity, again: metadata and potentially the contents;
  - IMEIs of the devices I used;
  - Any other types of information I did not think of.

In short - I'd like a summary like http://myactivity.google.com/, but from my GSM provider.

I'm not saying that all of this is collected and stored, but with GDPR we can demand a response and check. I couldn't find via Google any writeup by anyone doing such a request. If no one has done it I think I'd like to do it myself. I'm in a EU country and so is my GSM provider.