Nigeria's telecoms regulator said on Friday it had cut a fine on South Africa's MTN Group by 25 percent to $3.9 billion, and blamed a typing error for an announcement on Thursday it had reduced the penalty by 35 percent to $3.4 billion.
The Nigerian Communications Commission (NCC) hit MTN with a $5.2 billion penalty in October for failing to disconnect users with unregistered SIM cards, prompting weeks of lobbying by Africa's biggest mobile phone company to get the fine reduced.
After announcing on Thursday that the NCC had cut the fine by 35 percent to 674 billion naira ($3.4 billion), MTN said on Friday it had received a second letter saying the regulator had in fact intended to lower the fine to 780 billion naira.
"The information that was conveyed to them initially said 35 (percent reduction) but it was 25. It was a typo," NCC spokesman Tony Ojobo said.
Nigeria has been pushing telecoms firms to verify the identity of subscribers amid worries unregistered SIM cards were being used for criminal activity in a country facing the insurgency of militant Islamist group Boko Haram.
MTN makes about 37 percent of its revenue from Nigeria, and a reduced fine of $3.9 billion would still equate to more than twice its annual average capital spending over the past five years.
Its shares, which have plunged more than a quarter since the fine was announced on Oct. 26, closed down 3 percent at 135.74 rands.
"The regulator exercised its discretionary powers based on consultations with the federal government and other stakeholders," Ojobo said, when asked why the fine was reduced.
He added no decision had been taken on whether MTN would be permitted to pay in instalments.
Ojobo said MTN had two weeks, starting from Dec. 3, to respond to the NCC's penalty reduction.
MTN said the NCC had given it until the end of the year to pay the fine.
"Neither the first letter nor the second letter sets out any details on how the reduction was determined," MTN said, adding its chairman, Phuthuma Nhleko, would immediately hold talks with Nigerian authorities before responding.
The fine came months after Muhammadu Buhari swept to power in Africa's biggest economy, after a campaign in which he promised tougher regulation and a fight against corruption.