A CALL has been made for an independent telecoms regulator as it emerged nearly three in four mobile customers are overpaying for unused data at a total cost of £800 million a year.

A consumer survey reveals that 71 per cent of mobile customers with a SIM-only plan - or 12 million people - are overpaying for data they do not use, with those on bundled deals likely to be similarly affected.

Citizens Advice Scotland has joined it's sister group Citizens Advice to call for an industry-funded telecoms regulator that will fight the consumer's corner, similar to that in other essential markets from energy to water.

Citizens Advice which conducted the new UK survey, is urging more mobile networks to refund unused data or make it easier for customers to reduce their monthly allowance if they find they are wasting data repeatedly.

It also urged consumers to check their data consumption and switch to a cheaper deal if necessary, finding that those who are overpaying could save around £63 a year.

Last year Citizens Advice found that four million people have been charged for mobile phone they already own, spending £500m extra on contracts.

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It found three of Britain’s biggest mobile networks, EE, Three and Vodafone, continued to charge for handsets even after the cost has been paid off.

The consumer organisation says that the average amount of data wasted each month was 2GB, the equivalent of streaming three hours of video or 28 hours of music.

CAS policy manager Nina Ballantyne said it was time for a shake up to make telecom firms more accountable.

“An industry-funded, independent, telecoms consumer advocacy is a significant gap in the current telecoms landscape that CAS would see as a priority for government to address," she said.

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“The last time consumer advocacy arrangements changed was in 2003 when neither the iPhone nor Facebook even existed."

The study found that those who bought their contract in store were found to waste 4.2GB on average, while those who signed up online wasted 2.6GB, suggesting face-to-face sales practices could particularly be leading consumers to take up deals with excessive data allowances.

Citizens Advice, which has also previously reported broadband companies earning £1.2 billion annually by charging loyal customers more for their services, says an independent "consumer champion" should cover both mobile and internet firms. Complaints are currently handled by Ofcom.

Citizens Advice chief executive Gillian Guy said: “Mobile companies should be doing more to help their customers save on data they don’t use, especially when it’s clear people are consistently underusing their allowance.

“This is another example of mobile companies overcharging their customers. It’s time for a consumer champion to stand up for people and push for change on issues like this.

“While we wait for industry to improve support for customers, individuals can take action too. Anyone looking to save money should check their data usage and see if they can switch to a cheaper deal that matches what they use.”

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Digital Minister Margot James said: “People’s use of mobile data is growing steadily, but many are still paying for data they’re not using.

“We’ve made it easier for people to switch to better plans, including ones that allows you to gift unused data to family members or charities, and I’d urge people to shop around for a deal that works best for them.”

YouGov surveyed 4,070 adults online, 1,425 of them on a SIM-only plan, between November 29 and December 3.

Last year, Ofcom branded mobile phone providers’ pricing of contracts as “unacceptable”, and said up to 1.5 million consumers are overpaying for their phones.

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The communications regulator said its research showed that approximately two thirds of mobile customers on monthly bills are on contracts that ‘bundle’ the cost of their handset along with the cost of airtime.

While this works out as good value for money for most people, the watchdog said a “a significant minority”, estimated at around 1.5 million, continued to pay the same price after the end of their minimum contract period, meaning they were still paying instalments for a handset that had already been paid off.

Ofcom said this happens when providers are not transparent about costs when customers sign up for contracts, which it said was “unacceptable”.