I receive a number of calls from numbers that I don't recognize, so I block them. However, the continued calls are going to straight to voicemail. How can they be blocked entirely without filling my inbox?
Your probably blocking them at the HANDSET level with a feature of your phones software or an app. Its just rejecting a call and the default of rejected or unanswered calls will always be your voicemail if equipped.
If you dont want it to reach voice mail you need to block it at the NETWORK level. Usually if its available its a paid add on but its not foolproof. Scammers can and have called back from a different number each time and the number you blocked is basically pointless and just fills up your black list and highly unlikely they will re use those numbers.