Children's hit TV show Lazy Town has complained about the terms of a contract with an organisation that says it is "the leading provider of free educational resources to schools".
Stunning PR, the company responsible for Lazy Town's publicity in the UK, is one of at least 10 organisations that say they have unwittingly signed a rolling contract with a company called Infomat and it is costing them thousands of pounds.
Lazy Town - a children's programme featuring Sportacus, a superhero who promotes active living - signed a contract with Infomat to sponsor an obesity campaign aimed at schools. In return, Lazy Town hoped to raise the show's profile in thousands of schools across the country.
The company paid nearly pound;6,000 to advertise on Infomat's website and take part in email marketing campaigns targeted at schools.
Stunning PR director Suzane Noble said they were not very happy with the results.
"We put it down to a bad investment and thought nothing more of it.
"The next time we heard from them was when we received an invoice asking for another pound;6,000."
When she queried it, she was told to look at the terms and conditions. She then noticed that the contract was renewable.
"It is now six months later and I am being harassed by debt collection agencies."
At least 10 companies say they have had to renew their contracts with Infomat, including major London book chain, Foyles.
Foyles' academic account manager Ben Smith said the company was keen to see if if could raise its profile by using Infomat.
"We didn't see much come through in the shape of sales, but sometimes you expect that with marketing. But we were surprised to find out we had a rolling contract with them.
"We didn't want to pursue it, but it seems we are tied into a contract. We hate to throw good money after bad."
Clause 21 of the Infomat contract's terms says: "This contract will automatically be renewed after the annual period of contract (commencing on the date of the client's original written order confirmation).
"Exceptions to this clause are where the client notifies the company in writing, no later than three months prior to the end of the period of contract."
Senior Trading Standards officer David Sanders expressed concern about the contract terms while stressing that they were not illegal in a business- to-business contract.
Infomat is a subsidiary of RGS Europe, a "media solutions" company working in the education sector, and says it has been working with 24,000 schools, 700 colleges and a number of universities for more than eight years.
The company provides free resource materials, such as worksheets, exam guides and study guides, which can be accessed by teachers and students from the Infomat website.
An Infomat spokesman said: "We are very disappointed that a small number of companies have expressed their dissatisfaction as we pride ourselves on giving the best possible service.
"We have many hundreds of customers who are very happy with the service we provide and that is shown through the number of renewals we receive each year.
"Our terms and conditions are made public and are very open and transparent and do not differ from any gym membership, mobile phone company and any other similar service provider.
"Our main aim is to provide a good service to companies so we can continue to support schools across the country. This is something we intend to carry on well into the future."