This nearly always happens on the eve of the World Cup with an African team.
The media like to make out that these overpaid prima donnas won't get out of bed for less than L100,000-per-tournament (or whatever) when they should want to represent their country for free, because of national pride.
This isn't the way it is however. The players are striking because FIFA pay bonuses to the national FA, in this case the Cameroonian FA. The players are striking because they want the money to go straight to them rather than their national FA because there national FA is corrupt.
They want the money to go straight into their accounts so they can distribute the money as responsible adults to schemes and initiatives around Cameroon and beyond, after keeping whatever amount they deem fit. If the money is paid to the Cameroonian FA no one will ever see it again.
I think this position is admirable, and I hope they get what they want.