Why was the phone "blacklisted"? Failure to pay the bill? Reported as lost or stolen? That problem needs to be cleared before the phone can be used by someone else. Why would you send a blacklisted phone to your cousin in the first place?
From what I read (quick google search) Nigeria is primarily GSM territory so a Verizon phone (CDMA) will not work. So the phone you sent has two strikes. Chances are there is nothing you can do to get that phone working for your cousin in Nigeria. You could tell him or her to buy a pre-paid from a carrier in Nigeria that WILL work - and send the money if you want to help financially.
Why was it blacklisted?
When you say that it is not working with the internet service in Nigeria, what do you mean by this? Is it a global phone with a SIM card? Are you trying to connect via a WiFi connection or a cellular connection? If you are trying to connect via a cellular connection, your problem may be because your phone has been blacklisted, or that it was not unlocked by Verizon prior to sending it to your cousin, or a combination of both.
If it was not unlocked by Verizon, you will have to call Verizon to see if they will have this done without having it active on a Verizon account. You would probably have a problem with this, though, since it has been blacklisted.
It all comes down to my original question, why was it blacklisted? Did you not fullfill your contract with Verizon? Did you report it stolen? Is it stolen? Did you get it from someone else who had reported it stolen? When you can fix the blacklist problem, you will most likely have a better chance to fix your internet service problem.
Pretty sure the 9930 is global ready. the whole "blacklisted" thing is what you need to resolved for it to work as a cellular device. If you are just trying to use it as a WiFi device, then you'll probably need to provide some more info on what your are trying to connect to and what the actual problem is that is occuring...