Official figures from the Housing Ombudsman showed it received 15,112 complaints and new enquiries, and closed 15,877.
Although 81% of cases received being closed without the need for a formal investigation, the annual report revealed an 18% increase in cases that went forward to formal investigation, which are the most complex and difficult to resolve.
The Housing Ombudsman’s Annual Report and Accounts for 2016-17, shows continuous improvement in the service with increased productivity and high levels of customer satisfaction.
The review comes at a time when concerns about the treatment of complaints by tenants is under scrutiny following the Grenfell Tower disaster.
Politicians, including Labour MP Rushanara Ali, have called for a ratings system so tenants would be able to avoid poor-performing housing associations.
“Why can’t we have league tables for housing associations so we know who are the worst offenders,” she said.
There was good news for those who have turned to the service. Despite the increase in these cases, determination times significantly improved, with 96% of cases determined within 12 months compared to 59% in 2015-16.
David Connolly, interim housing ombudsman, said: “The improvements in our service reflect the dedication and hard work of our staff.
“Through their efforts we have made a difference for many complainants, and we have played our part in supporting the sector to improve complaints handling and develop their services.”