More than 137 lawyers, social workers, financial counsellors, NGO workers and professionals were surveyed as part of a report to be released by the Telecommunications Industry Ombudsman and Community Legal Centres Queensland on Friday.

The most common phone or internet issues reported by clients were not having enough money to pay for bills, increasing debt, legal action for debt recovery, misunderstanding their contract, late bill payment, overselling, problems moving house and language barriers.

As a result, some clients suffered mental health issues, unemployment, housing issues, had services shut off, acquired a poor credit rating or had legal problems.

Many people did not know they could complain about their service or to whom to complain.

Payment plans, financial education and restrictions on overselling plans were listed as the top ways to help people avoid problems with phone or internet companies.

Almost half of workers in the community legal sector reported hearing from clients with a phone or internet problem every week.

More than half said their clients did not know how to complain about problems with their phone or internet service.

The most common help given to clients was advocacy, referrals to other professionals or organisations and communicating with third parties.

Community Legal Centres Queensland director James Farrell said phones and the internet were central to people's lives.

"The message from Queensland's community legal sector workers is, don't feel like you're on your own," he said.

"In tough times, mounting problems have a domino effect, one problem leads to another, and on to another.

"Our members and wider professionals in the field can offer support and advocate on your behalf."

In 2016-17, 28,988 residential and small business customers contacted the Telecommunications Industry Ombudsman with a problem with their phone or internet service.

That was a 42.7 per cent increase in complaints from 2015-16.

Customers are advised to try to resolve their complaint with their phone or internet provider first.

If that fails, they can contact the Telecommunications Industry Ombudsman by visiting www.tio.com.au or call 1800 062 058.