Spam calendar invites from 16700700.com

Anyone else's calendar getting completely spammed with invites from 16700700.com or 35700700.com ? If you are, you are not alone - my calendar has been absolutely crammed with them. As far as I can tell there is no malware or anything security-wise that I have done to allow access to my calendar, it would appear that anyone can invite themselves to any calendar - an obvious security issue.Its easy to remove them, by right-clicking and choosing Decline, but shortly after doing this for a single item on my calendar it was absolutely inundated with them, so don't do that! By declining you notify the person that it is a valid email address for the calendar. Update: 14th November 2016 - Apple engineers have got back to me letting me know that they are working to resolve the issue as it is a huge issue affecting lots of Apple iCloud accounts and that they have seen a sudden increase in the requests over the past 2 weeks. On other more worrying news I now have bogus photos requests too.The most important things you should do is: Change your iCloud password to something new, and turn on 2-factor authentication for your account.