The Communication Workers Union (CWU) has called on MTN chief human resources officer, Nhlanhla Qwabe, to step down in its latest war of words with the network.
The union is set to meet MTN in court on Tuesday after applying for an interdict against the company regarding its outsourcing plan.
Last week, the CWU applied for a court interdict against the network provider following the company's decision to outsource a portion of its call centre facility to a third-party vendor. The union claims that it had not been properly consulted over the move.
CWU president Clyde Mervin said that MTN had been victimising staff members and shop stewards amid threats of strike action.
The union is also calling for a salary increase and the conversion of temporary workers into permanent staff.
"We cannot allow our members to be treated this way. We are going for them. There is a war to come," Mervin told Fin24.
"People say they know us for all calling for people to step down, but that is exactly what we are doing. We want Qwabe to step down," he added.
MTN earlier said it will adopt a hybrid outsource model which would result in retaining some of its call centre facilities, while others would be outsourced to an experienced third party vendor.
This was in a bid to "optimise operations and enhance customer experience."
Meanwhile, MTN and CWU are set to meet on Friday again in a "long over-due" meeting, said Mervin.
MTN confirmed that the meeting with the union was indeed scheduled to take place on Friday.
"We are looking forward to a constructive meeting, where all parties will conduct themselves in a respectful and professional manner," Qwabe told Fin24.