The Property Ombudsman dealt with 2,518 complaints relating to lettings, 1,669 relating to sales and 780 for residential leasehold management.
The biggest awards were £17,644, £20,200 and £21,439 respectively, and the average awards were £635, £742 and £273 respectively.
Management was the top cause of lettings complaints last year, but communication and record keeping remained as the top cause of sales complaints.
The manner in which agents dealt with complaints was again in the top three causes of complaints for lettings, sales and residential leasehold management.
Of the formal complaints about letting agents, 67 per cent were supported by the Ombudsman: 50 per cent of those complaints were made by landlords.
The top causes of lettings complaints were firstly management, then communication and record keeping, followed by complaints handling, tenancy agreements, inventories and deposits.
Despite a significant increase in complaints, compensatory awards paid by agents to consumers only rose by 1.4 per cent to a total of £2.2m.
The annual report claims this is an effective barometer for the sector that progress is being made with agents generally complying with the TPO Codes of Practice.
The average lettings award was only £635.
On the sales side some 63 per cent of complaints were supported by the Ombudsman: 67 per cent of complaints were made by sellers, while 29 per cent were made by buyers.
The average sales award was £742.
The top causes of complaints about sales agents concerned communication and record keeping, followed by complaints handling, then marketing and advertising, and disputes over instructions/terms of business/commission/termination.
Katrina Sporle, who retires from the role of TPO later this year, says: “2019 was another busy year for TPO. Complaints ascended year on year again and we also saw the complexities of cases increase, particularly in the residential leasehold management field.
“Our Customer Services team responded to a record number of people, over 30,000 initial enquiries raised, with nearly 10,000 of those received through our 24/7 online chat service, a seven per cent increase on 2018.
“Just over 25,000 enquiries that did not go on to become formal complaints saw TPO effectively assist consumers in other ways, whether that be signposting them to the correct place or person or giving advice and guidance to promote a local resolution between them and the agent.
“TPO has translated its work in the initial enquiry stage into a self-diagnostic tool. Still in its piloting phase, we hope to promote the online tool this year.
“2020 has already brought a huge challenge with the outbreak of Covid-19. TPO acknowledges that the current situation is an extremely difficult one, for agents and consumers alike. TPO is here to help as best it can and is operating a full service. Consumers can still make a complaint at this time and the property industry can access information, guides and advice via our website.”