Spam calendar invitations in Asian characters added to my calendar DAILY--How can I stop these?

Recently, I started seeing invitations in Chinese added to my calendar on a daily basis. I have followed forums for suggestions on how to remove them, but all trails lead me to no solution. When I look at the invitation, there are a LIST of email addresses, so clearly spam. There is no way to decline it without looking/clicking on the invitation. I have used the "report junk" option, but they're still being added daily. I tried going to the icloud to turn off calendar invitations, however, there is no pathway there to turn them off. My phone is an Apple 12, my desktop an iMac. Is there anyway to figure out how this is happening and how stop it. It seems that Apple and Microsoft are both aware of this problem, but no one has a straightforward solution. If this can't be resolved, are there other safer calendar-apps that I can use? Thanks so much!