Resolver surveyed its users and found that a quarter of people had encountered issues such as blocked switches, meter reading discrepancies and demands for payment long after the switch had been completed.

One in 10 switchers had experienced multiple problems.

The survey also found that 80% of people were unaware of compensation rules introduced last year to help ensure that energy switching is a smooth process. Under the rules, £30 will be paid by the new supplier if a customer is switched by mistake, or if the switch takes longer than 15 working days.

The news comes the week after Ofgem announced that more than 1 million people had been overcharged during the switching process.

According to the energy regulator, about 1 million customers were overcharged to the tune of £7.2m by 18 suppliers who did not follow the price protection rules.

Resolver says this is particularly frustrating as the benefits of switching energy providers are considerable, with the average consumer potentially saving hundreds of pounds.

In 2020, just under 6 million people switched suppliers. However, millions of people are still stuck on tariffs that are expensive or not reflective of their energy consumption.

Of the 51,000 complaints made to energy companies through Resolver in the past two years, one in 10 concerned contract disputes, transfer issues and credit problems related directly to switching energy suppliers.

Alex Neill, Resolver’s CEO, said: “While it’s frustrating that some energy firms are still getting the switching process wrong, people should not be put off changing providers. The savings far outweigh the problems.

“What’s important to remember is there are clear rules set by the regulator on switching – and if things go wrong, you can turn to the free energy ombudsman service for help.”