To Blacklist a Stolen GSM Phone's SIM and Retain my Number

ON THE MTN NIGERIA NETWORK:
Go to the friendship center with the necessary documents. I.e., the SIM pack, a police report, a court affidavit and the sum of 980 naira for a welcome back pack.

From www.mtnonline.com/support/topfaqs.asp#15

ON THE VMOBILE NIGERIA NETWORK

• Call Customer Care immediately at 111 to report the line stolen so as to get the line blocked. You may also visit any of our Vstores or Vshops to report the line stolen.
• To retrieve the line (SIM swap), you must visit one of our Vstores or Vshops. Come along with your SIM Certificate, a form of identification (Passport, Driver’s License, etc) and 1,500 naira.
• In the event that you are unable to find your SIM Certificate, you will need to produce a Police Report, a sworn affidavit, a form of identification along with a 1,500 naira swap fee.

From www.vmobile-nigeria.com/stolen-phone.htm

See the news article, 'Time to Fight Cell Phone Theft', by Shina Badiru, for more information.

pele it happened to me once.. anyway u can get your sim back. service providers don't block phones even with your IMEI. u have to contact your phone company, they will be the one to tell the providers to block the phone,, but if u know this is Nigeria,,, getting your phone company to do what u want mite turn into hell. so get your line back & get a new phone