Meetings are disappearing

I'm hoping someone could answer a question for me. There have been instances
where I have scheduled a meeting and the attendee has accepted. Then I've
emailed them a note directly from the meeting appt. (Actions - Reply with
message). If that email is then deleted (clicking on the X) would that in
turn delete the meeting from their calendar even though they previously
accepted? Meetings keep disappearing from calendars and this is the only
thing I can possibly point to that might be the cause. Thanks!