Since then we've been deluged by calls from readers who feel they have been hard done by at the hands of the power giants. In each case the complaint is the same, and goes like this:
The retailer signed up for a new gas or electricity contract at a good rate
A year later their bills shot up. They contacted the supplier, who told them they had missed the window in which they must give notice if they intend to end the contract and look for a new deal
The retailer was told they had been 'rolled over' into a new contract, locked in at a higher rate, and for a longer period than the original agreement.
In every single case, the callers told us that they had not seen any correspondence from the supplier reminding them that they must give notice or suffer this 'assumed renewal'.
In truth, they probably did receive a letter, but didn't realise it. Barry Jones of Colwyn Bay, Conwy, told us his supplier sent him a letter that began "To protect your price for two years, you don't have to do a thing".
But on a second page it revealed that the rate on offer was almost twice what he currently pays. After assuring him again that he did not need to do anything, the letter revealed that if he did not accept the new terms he must contact the supplier to cancel. Incidentally, Barry's supplier has announced record profits, up 58% in 2009.
Our readers' experiences suggest that companies must be more transparent in explaining the consequences of missing the deadline. That's something we'll be taking up with Ofgem, the industry regulator.
For now, hundreds of stores are wasting thousands of pounds a year because of this policy. Our Cancellation Day initiative, launched in 2009, helped to publicise the problem, but as the sad experiences of our callers this month confirm, many are still falling into the trap.
Please make sure you're not one of them.
Dig out your gas and electricity contracts and check when they're due to end and when the notice period begins.
Write both dates in your diary Once the notice period begins, put your notice in writing you may want to send it recorded delivery
Contact other suppliers direct, or use a comparison service
Put the notice of your new contract's termination date in next year's diary