Blocking a single number!

My sister got a phone for christmas, but is now getting horrible text messages from an unknown person. We have no idea about who it is, and i thought there was a way i could block that number from ever ringing or texting my sister again. There is something about barring all incoming numbers or something like that, but you need a password to do that, and even if you didn't need a password, my sister wouldn't want to block ALL calls. But i cannot figure out how to block or barr one number, but i am sure there is a way! If someone could help i would be extremely grateful!!!!

My sister has the Nokia3310.

maybe your service provider can help you
just say the number and they will block it

and you can make a script and use free sms gateways (if you find these) and spamm this bastard (i've tried this, it's really cool, but now i don't have a gateway to send sms to my country mobile phones)

lol cool!

Answering your mobile phone
When you answer the phone, just say "Hello" rather than giving your name and number.
Let callers identify themselves first if the number is not displayed on your handset.
Never give out any information about yourself unless you are certain you know the caller..
If you have Callback active, most handsets will allow you to divert the call to your mailbox without answering..
Be careful not to leave alternative contact details on your mailbox greeting..
If you're female and concerned about leaving a message, try asking a male friend to record a greeting for you - many malicious or nuisance callers are put off by a male voice..
Don't help malicious callers by giving away information about yourself - ie: your marital status - especially if you're female..
If a caller asks you to confirm your number, ask them what number they want and simply tell them if they are right or wrong..
Advise anyone else who may use or have access to your mobile phone, to follow the same procedures..
Some malicious callers may want nothing more than to have a conversation. Remember malicious callers use the phone to hide behind because most would be too frightened to say the same things to your face.
Unwanted phone calls
Check to see if the caller's number is displayed before accepting the call and ask your friends not to withhold their number when calling your mobile.
Do not say anything when you answer the phone, a genuine caller will speak first. A malicious caller will probably hang up.
Some malicious callers may want nothing more than to have a conversation. So calmly place the mobile down and ignore it for a few minutes before ending the call.
Remember malicious callers use the phone to hide behind because most would be too frightened to say the same things to your face.
Don't reply!
Keep the message on the phone as evidence in case you need it. If your phone has an archive facility it would be best to save it there as the 'Inbox' only retains messages for a couple of weeks.
Scroll to the bottom of the message and make a note of the sender's number or originating details.
If you feel it is appropriate (ie: persistent/unpleasant or threatening messages), take the information to the Police, who will contact the originating Mobile Network or contact the Nuisance Call Bureau for further advice.
Some common misconceptions
It is NOT possible to block an individual number from making calls to one phone.
When a number making nuisance calls is identified, you will NOT be provided with that information.
The law in Scotland differs from England and if the caller making the malicious call becomes known to you during a police investigation, you will not be able to drop proceedings, without the consent of the police.
If none of this advice stops the unwanted calls or messages, please contact us and our Customer Care team will do all they can to help you. Please remember to provide your name and mobile phone number, full details of the problem you are having and what steps you have taken to date. Simply click on the 'Contact Us' button below.