Telstra has been named the most complained about telco up to March. Making matters worse, Telstra had a major outage Monday night lasting through to Tuesday morning, leaving customers unable to make of receive calls.

The Telecommunications Industry Ombudsman claimed 40% of the 17,777 complaints received last quarter involved Telstra. Complaints surrounded mainly Telstra’s mobile services, however the overall complaints surrounding mobile services decreased in the March quarter.

Poor mobile coverage became the third-biggest issue for users across all telcos, and a rise in complaints about contract variations like price rises were noted.

Financial hardship complaints rose from 397 to 433, largely centered around mobile services.

Ombudsman Cynthia Gebert has said, “While complaints about mobile services decreased this quarter, these problems continue to make up just under half the complaints we receive.

“Given the importance of mobile phones to Australian consumers, it is concerning this proportion continued to remain high.”

She mentioned there had been a “dramatic” lift in home internet complaints.

“Substantial increases were recorded in complaints about getting connected to an NBN service, problems with a bill, and service quality issues such as drop-outs and slow data speeds.”

Complaints regarding Optus surged to 6436 in the December quarter with users venting frustration after a data breach. 5322 were decline in the three months to March.

TPG, Vodafone and iiNet recorded approximately 2400 complaints collectively.

A Telstra spokeswoman has said it is making progress in reducing overall complaints made to the ombudsman, and figures fell 37% compared to the same period last year, and over 60% compared to two years ago.

”Any number of complaints is still too high, which is why we place such importance on initiatives that remove customer pain points and improve our overall service,” she said.

This report comes after Telstra customers were hit with a widespread outage preventing customers making and receiving calls from Monday evening to Tuesday morning around 10AM.

Reports of mobile service problems began around 10PM AEST across Sydney, Melbourne, Perth, Brisbane, and Adelaide.

The spokeswoman said this outage was caused by “a planned upgrade to our network that didn’t go to plan and had flow-on effects”.

“We’re sorry this occurred and we worked through the night to get things back up and running as quickly as possible.”

It was reported majority of consumers affected were located in NSW and Queensland, and 000 and mobile data was not affected at any stage.

Tuesday afternoon was dedicated to fixing a second issue, with some customers unable to call landline numbers from mobiles.

“For now, just adding the area code to the start of that will fix it while we work that one out,” the telco tweeted.

A TPG spokesman has said a quick and efficient resolve of customer issues led to a 16.8% reduction in TIO complaints compared to the same period last year.

An Optus spokesman said they had a 17% decrease of complaints year-on-year.

“Optus continues to act on its commitment of doing better for our customers to regain their trust,” the spokesman said.