Consumer complaints in Australia about telecom operators fell more than 20 per cent year-on-year in Q3, with Vodafone and Telstra improving but Optus facing an increase.

A report from the Telecommunications Industry Ombudsman (TIO) showed that total complaints per 10,000 services in operation in Q3 dropped 20.3 per cent to 5.5 from a year ago. The ratio was down 15.4 per cent from the previous quarter.

The TIO said it was the lowest quarterly result since it started publishing its “Complaints in Context” report.

Vodafone’s complaint ratio dropped 66 per cent to the lowest in the mobile industry, 4.1 – in Q3 2014 it had the highest ratio of complaints (12.2) out of the country’s three mobile operators.

Telstra’s ratio fell 19 per cent to 5.5 from a year ago, while Optus saw its complaint ratio jump 45.6 per cent to 6.7. A year ago in Q3 its 4.6 ratio was the lowest among mobile operators.

Mobile related complaints, which were down 31 per cent year-on-year to 10,340 in July-September, represented 40 per cent of the total, down from 49 per cent a year ago.

Complaints about coverage accounted for 7.5 per cent of new complaints about mobiles — down from 10.9 during the same period last year. Excess data charge complaints also decreased sharply from 2,524 in Q3 2014 to 1,254 last quarter.

Billing and payment issues — across mobile, internet and landline — accounted for 44.3 per cent of all new complaints during the quarter.

The TIO said all companies recorded an improved performance in Q3 compared with the previous quarter — which itself had generated a then-record low average. “It is also encouraging to see that the remedial measures put in place by Optus after some recent operational issues have generated a strongly improved performance in the most recent quarter,” it said.