A system error left more than 20,000 British Gas customers out of pocket last week, after twice the normal amount of money left their bank accounts, according to Thisismoney.co.uk.
The mistake affected billpayers who paid their gas and electricity bills by debit card on Tuesday. The correct amount was billed on the day, but the same amount was then taken from their bank accounts three days later.
Some were left unexpectedly overdrawn by the error, meaning they then had to pay unauthorised overdraft fees as well as their bill. British Gas said customers would have to wait until Wednesday to get their money back.
An expert at thinkmoney commented: "This is an example of one of the many unexpected costs that can leave people out of pocket, and in some cases overdrawn. We all expect to have to pay for the occasional car or boiler repairs, but this demonstrates how some costs can go undetected until you check your bank balance.
"For this reason it's a good idea for people to either make sure they have an agreed overdraft facility in place, or to find a bank account that doesn't charge for accidental overdrafts."
If you're looking for a bank account that doesn't charge for unexpected costs that take you into the red, the thinkmoney Personal Account could help. It also doesn't charge for missed or rejected payments, giving you less to worry about.