Many parts of Africa are so backwards, or there are so many scams and dangers, that either they won't even recognize how to turn on a cell phone (let alone charge one up or use one--assuming they have electricity to charge one), or they would be taken away by bandits and/or fake (or real) police checkpoints the first time they pass one. And this is especially true in one of my least favorite parts of Africa--the West Cape (particularly the southern part) and nearby countries just south of the Sahara Desert.
Now, if they did get significant infiltration of Internet access, people in those backwards parts would have trouble using it. Nigeria has Internet access--for scammers that are pulling those famous 419 scams. However, scammers aside, very few people actually know how to use it. They are probably even worse off than I was when setting up my first Windows computer. They lack access to clean versions of Windows or Mac software or the knowledge to set up and use Linux, and the crap versions (always pirated) are full of rubbish. They have to worry more about scam sites, and they don't even have access to proper Norton antivirus (just outdated, pirated discs that are rubbish). They could not pay for a proper copy of Norton, let alone one of the better antivirus programs. They would have trouble getting the free versions of Avast and AVG, with all the scams going on there.
The result is that they have to worry themselves sick about worms and viruses. In developed countries, we have to be careful and keep our antivirus up to date (usually, running one continuously and another one in limited mode or for scans only). In Nigeria, they don't have that antivirus--so their computers are more likely to be infested. And, when they do get a worm, they are more likely than not to run into yet another scam. As they don't have good OS discs, removing worms is much more involved. The U-Fix is as likely to be another scam, plus most Nigerians are not well enough educated to use them properly (try having one of them replace a dead hard drive). Not to mention, their electricity is so unstable that it can destroy a computer faster than a worm.
With all that in mind, and given that most Central African nations lack education enough to properly run a computer, it could be longer before the witlesses start seeing much impact there from these devices. And, as those things cost money (that they don't have), I expect that it will be a while before sufficient infiltration by the Internet reaches this gruesome region to cut off the witlesses.
And when it does (if), I would hate to be on a Nigeria mission for any religion. The witlesses will face intense persecution. And, once any Nigerian can figure out how to access sites exposing Christi-SCAM-ity as a major source of slavery and of their many problems, the missionaries will cease being welcome there. They will have to resort to more underhanded stunts (some involving acts that may qualify as kiddie porn if posted in detail) and actual force to gain a presence, leading to civil war. Of course, most of them will foolhardily remain there. And the witlesses will remain there once they are driven out by the people.
Hey, if they are willing to expose elderly members or children to pepper spray, gun fire, vicious dogs, grueling heat or cold, diseases, and bans from governments (along with civil wars), why would they stop when the witlesses are exposed as a source of their major problems? And why would they stop even as we are getting nearer and nearer the Age of Aquarius, at which point the whole Christian paradigm should rot out and become very unpopular?