You can stop unwanted phone calls by:
Open the Phone app. Tap an incoming call from the number you want to block. Tap Block/Report Unwanted Number.
You can use Google Voice by following these steps.
- On your PC, visit voice.google.com.
- Open the "Calls" tab -> click the "More" icon (the icon with three dots) -> select the number to block -> click "Block" to confirm.