[tsac]

Ok , the common link is this vendor 179. MTN does offer blackberry BIS plans and various data packages. I don't know who or what a vendor 179 is but if MTN has agreements with a provider to pick up their cell calls and that 179 provider does not have a BIS or blackberry service then it all stops. The phone if locked will not work on another carrier for most services.
MTN site for your area it seems clear they offer service and you can try calling MTN directly. Give them the IMEI number and they should be able to validate it.
Check to see if the spelling of the work Blackberry is in upper case not lower case.
Look at the serial numbers and PIN numbers. The pin is usually 8 digits/letters the IMEI is usually 15 digits