Continuous spam calls

All such calls are scams from criminals attempting to steal your personal and financial information. The callers will often use number spoofing to pretend they are calling from a legitimate business. The correct course of action is to hang up on them, repeatedly if needed. 

Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

You haven't been hacked. Anyone with your phone number can call you. These outfits even call random phone numbers. There have even been reports of people without Apple products getting them. You can check with your cell provider to see if they have any spam filter or you can just set your iPhone not to ring on any calls from numbers that aren't in your Contacts. That's what I do.