A survey for Citizens Advice suggests that 71% 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.
The charity 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.
The average amount of data wasted each month was 2GB, the equivalent of streaming three hours of video or 28 hours of music.
People 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, the group said.
Citizens Advice, which has previously reported on mobile phone companies continuing to charge customers for phones they have already paid off and broadband companies earning £1.2 billion annually by charging loyal customers more for their services, is calling for an independent “consumer champion” for the two industries.
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.”
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.