degrees is taking on 60 temporary staff members this week to deal with customer issues but are warning there could still be delays for the next fortnight.
The drive for temps comes after a large number of customers complained about unexplained charges in their bills, double-billing, and issues with the company's mobile app.
Spokesman for 2degrees, Matt Bollard, said the issues stem from the telco's problematic switch to a new customer management software system.
He said he was not aware of systemic issues that would affect billing, but that 2degrees had carried out four or five billing runs in a quicker period than usual.
"We're experiencing a number of billing related queries, which have been complicated by the need to send several billing runs in a short period of time, which create increased call volumes on an already busy Call centre," he said.
Customers have complained on the company's Facebook page that they are waiting for hours or days to get a response from 2degrees.
"46.28mins and waiting, trying to get through is a nightmare," said a customer.
"2 Days - still waiting for a reply. No connectivity for three days now. No phone for 2," one wrote.
Others have complained of issues topping up their phones on prepay, saying they are being overcharged.
The 60 extra staff are on top of 20 temps 2degrees took on last week, Bollard said.