Good evening Mona and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the zip file unzipping automatically.
I would love to help you with this topic.
What is going on is that Safari has a default behavior that unzips files automatically.
You can change that: https://wiki.umbc.edu/pages/viewpage.action?pageId=31919091
The other thing you can do is just to re-zip the file once it has downloaded (using a right-click or Ctrl-click and selecting “Compress”).
Let me know how that goes.
Best regards,
Geoff B.