Over a third (39%) did not consider whether their agent was regulated, which would involve the agent signing up to a code of conduct or working under a regulatory body.
Londoners are most likely to experience bad agents, with 83% making a complaint in the last five years, while just 35% complained in Scotland just 35%.
Mark Hayward, managing director at NAEA said: “It takes a lot of hard work and research to ensure you are ticking all the right boxes, and no doubt people come across many challenges along the way.
“An estate agent should really be there to help this process, not hinder, and therefore the choice of which agent to go with is an important one.
“With the extensive administrative tasks and processes involved in buying or selling a home, communication between agents and homeowners is essential.
“It’s the estate agents’ role to make these processes seem as pain-free and seamless as possible, which regulated agents endeavour to do.”
The biggest complaint in the UK was about estate agents’ communication skills, as 21% said their agent failed to call them back or chased them too much (21%).
An additional 13% claimed their estate agent did not tell them about known faults in properties they were looking at, while one in ten (11%) said their agent made promises it failed to see through.
