Complaints to telcos are on the rise following an all-time low just seven months ago.
The Telecommunications Industry Ombudsman (TIO) calculates complaints from landline, mobile and internet services from residential and small businesses by measuring the amount of new complaints for every 10,000 services-in-operation for Australia's five biggest telcos.
During the quarter from April to June 2016, the TIO received an average of 6.4 new complaints for every 10,000 services. The average complaints in the previous quarter was 6.2.
The TIO noted that complaints historically drop during the second quarter.
Optus once again received the most complaints with 7.7 for every 10,000 services, followed by Telstra with 6.8, Vodafone with 3.8 and Pivotel with 1. However, Optus has shown signs of improvement since last year, fielding 8.5 complaints from April to June in 2015.
Australia's fourth-largest telco Amaysim was once again the least complained-about telco with only 0.8.
Complaints have fallen by 1.5 per 10,000 services year-on-year since the TIO began publishing its data in 2013, reaching an all-time low of 4.8 from October to December of 2015.