For the first time in history, Nigeria's Communications Commission, the country's telecommunications regulator, has issued mobile phone firm MTN Nigeria, with a record $5bn (£3.5bn) fine for failing to disconnect subscribers with unregistered Sim cards bought before January 2012.

From that date anyone buying a Sim card in Nigeria has had to register it under their name by law. Phone companies were told to register their existing customers' Sim cards, which MTN Nigeria - the biggest telecommunications firm in Nigeria - has failed to do.

In the meantime Nigerians continue to complain about poor services from mobile network operators and blame the regulators for not doing enough to solve the problem.