iCloud Calendar events disappear

Events from my iCloud calendar disappear. I was forced to do manual backups of all my calendar because sometimes my events just disappear. I loose future events and past as well.

I have contacted Apple support and they told me to just do the backup but I think it's ridiculous. I have not chosen Apple products to care for such basic things as calendar events!

Please do something with it! If it happens one more time I'll switch to Google calendar because it has never happened there.