How do I delete uninvited guests who have never been contacts?

Hello, let me create a case for you and assign it to our Tech Support Team so they can check on your issue. Please send us details including your RC number, name and contact number at community.support@ringcentral.com. Looking forward to hear back from you.

Not sure, but please check the below link once, hope this can solve:

https://community.ringcentral.com/questions/95499/how-do-i-delete-a-contact.html

I appreciate the help! I have used my cell phone this whole time. I signed in on a desktop, signed into the app on desktop, and was able to delete the uninvited guests. Thank you!!