Motorola Moto G — Unwanted contacts

I had the same problem. This is how I solved it: Go to Contacts, pop the menu up and pick Delete, select the "unknown contacts" you want to delete, by checking them one by one, press delete.

My moto G is adding blank contacts repeatedly, by the dozen! Is there a way to delete them all at once? Why is it doing this?? Just started in the last week (have scanned for viruses).

Well that seems really odd as the phone should not add unwanted contacts.

Do you use a Google account and is the sync turned on?

I would try to reset the phone and see if unknown contacts are coming back.

Basically the mobile phones never save unwanted contacts but i would suggest for factory reset option.