A hearing into whether Telkom abused its market dominance was adjourned in the Competition Tribunal on Wednesday.
The tribunal would consider the evidence and make a finding in due course on whether Telkom abused its dominance in the telecommunications market.
Should it find against Telkom, the Competition Commission wanted the company to be fined R3.5-billion, SABC reported on Tuesday.
In its heads of arguments, Telkom argued that its profits had been declining in the past few years.
The penalty would be "catastrophic" and would affect its "operations and irretrievably jeopardise its viability", Business Day reported on Wednesday .
The case was referred to the tribunal in 2004 after the commission found Telkom guilty of charging excessive prices to smaller independent companies -- which relied on the company's network infrastructure to provide data services like the internet and SMS.
Telkom denied this.
The commission also found that Telkom was discriminating against the independent service providers in that it charged lower rates to its affiliates.