Blocking someone from calling or texting you can be done for many diverse purposes. When a relationship sours and you have no desire to hear from a particular person anymore but that person continues to try to contact you, the best thing to do is to simply block their number. Though the intricacies of blocking a person from calling or texting you may vary from phone to phone, in general all phones operate in the same way when it comes to blocking a number.
Open your contact list.
Scroll down to the name or number of the person you want to block.
Select that person's phone number.
Go to the contact's settings.
Scroll down until you find the "block contact" or "reject number" buttons. Select the appropriate button. This will block both calls and texts from that contact. If you cannot find these buttons on your phone, consult your phone's user's manual.