Telkom Chief Executive Officer Mombulelo Moholi resigns before the end of her contract, as the company fails to pick up after a long stint of bad results.

Telkom announced on Monday that Moholi notified the board of directors of her decision to step down before the end of her contractual term on Friday.  She has given the board the requisite six months notice in order that a new CEO may be found before her official departure, the telecoms operator confirmed.

The move comes less than 18 months after she joined the organization – which specializes in the provision of fixed-line connections -, when Moholi in turn replaced ex-Telkom acting CEO Jeffrey Hedberg in March 2011, and was charged with turning the telecom operator’s luck around which has been experiencing serious challenges.

The operator – which is 40 percent government owned – has seen business flailing for some time, due to the prevalence of fixed-line subscriptions declining in South Africa, as the population turns to mobile phone usage; with latest statistics from the 2011 Census showing 88.9 percent of South African households now use mobile phones, whereas only 14.5 percent of households has a fixed-line connection.

The company has also attempted to expand in to the Nigerian market via mobile unit Multi-Links, an action that proved unsuccessful in grabbing market share and has caused Telkom to suffer losses revealed in 2011 in the region of 5.7 billion rand ($650 million) .

Telkom announced that it would first fill the vacancies on the board of directors – ensuring that the required eight positions are filled – before it turns to hunting for a new CEO.

“The board will embark on a process of finding a replacement CEO once it has filled the current vacancies and there are at least eight directors as required by the memorandum of incorporation. The process of filling the vacancies on the board has commenced and announcements will be made in due course,” the Telkom statement said.