Some typos change the meaning of words, or lead to funny mistakes we can all laugh at. Others are matters of millions of dollars.

MTN has been having some problems in recent times with Nigeria’s telecom regulator, the Nigerian Communications Commission (NCC). The company was fined $5.2bn in October for failing to cut off unregistered users.

After an appeal from the company, the NCC announced that the fine had been reduced to $3.4bn. However, it later announced that it had been a mistake in typing; and that the amended fine is rather $3.9bn.

Talk about an expensive mistake.

“There was a typo. The reduction should have been 25%,” Spokesman Tony Ojobo told the Bloomberg news agency.

“We saw the mistake and had to fix it.”

MTN are expected to pay the fine before December 31.