How does one disable the OnStar is a 2019 Buick Regal TourX?

I sat in my Buick after I had turned the car off for about 4 minutes.  I had
opened the window b/c it was hot.  Some features like radio, windows are
operational when car is turned off before driver door is opened.  All of a
sudden I hear something under the hood almost like a fax was being sent.  At
this time I had a meeting.  Get back from the meeting 20 minutes later and
car won't start.  The engine won't even turn over.  I had 2 people try to jump
the car and it still would not start.  Called AAA for assistance.  While waiting
some 2 hours later, I hear the same noise under the hood (fax machine
noise) while sitting in my non-operational vehicle.  I get behind the wheel and
the vehicle starts.  

How does the battery drain after 4 minutes sitting in the car after it's turned
off.  Is it possible that GM sent a disable code since I quit OnStar?