* South Africa's Telkom appointed Jeffrey Hedberg as Acting Chief Executive last week but its leadership crisis deepened last week when Chief Financial Officer Peter Nelson resigned, following the early departure of CEO Reuben September.The departures come at an inopportune time for SA's fixed- line operator. It has recorded a substantial decline in profit this year after it disposed of its stake in Vodacom and after write-offs from its ailing Nigerian unit, Multi-Links and an impairment on its Africa Online business. It is understood that disagreement over the ailing Nigerian Multi-Link business also influenced Nelson's decision.