Currys PC World has been told that it must make extended warranty terms clearer to shoppers after a regulator investigation found its sales practices could be misleading.
The Competition and Markets Authority (CMA) carried out a mystery-shopping exercise that raised concerns Currys PC World may be mis-selling extended warranties.
It found that more than a fifth of store staff incorrectly told shoppers that extended warranties cover cosmetic damage.
The CMA also found that a fifth of staff were unable to provide shoppers with a quote, which is a legal requirement before selling these kinds of warranties.
Which? consumer rights expert Adam French said: 'This is a welcome move and we look forward to seeing Currys PC World swiftly implementing these changes.
'It must ensure customers are armed with the correct information when making a decision about extended warranties.
'We would also urge customers to read the terms and conditions before buying an extended warranty as their right to return, repair or replace an item may already be covered under the Consumer Rights Act.'
Currys PC World has promised to address the issues raised by the end of November 2019.
It agreed to carry out more staff training, improve its advice leaflets on extended warranties and provide more information at till points.
It also says it will carry out its own internal mystery-shopping and customer surveys to monitor how effective these measures are.
Extended warranties cover repairs for any product faults that come up after the manufacturer's warranty runs out.
They cover an appliance for a set period of time, such as a year, and cost an additional fee.
Retailers offering these kinds of warranties for electrical products must give shoppers certain information before they sell them.
Retailers and other warranty sellers must: