Call your carrier and have them limit the number of rings, as you indicate "still rings constantly" or put the phone in a DO Not Disturb Setting at least for iPhones. Also whoever said to report each number to Malware is also correct. I do all three and have seen much improvement. And if I don't recognize a caller ID then don't answer I don't care if is was someone that really wanted to reach me as they would leave a voice mail. PS: Apple Sr Techs recommended Malwarebytes to me for a nation-wide Safari scam which they could not fix. WHA-LA ! Malware stopped it immediately.