- Save the number you want to block in your contacts temporarily (Create New Contact) . You can use a fake name.
- Go to Settings>Phone> Call Blocking & Identification>Block Contact>Choose the fake name created and automotically will save it in blocked names.
- Go to your Contacts, look for the fake contact and erase it (Contacts>fake contact>Edit>Delete Contact - at the end of the options) and that's it. Your phone will save the number but you don't have to keep the contact.