Every month I hear from retailers realising belatedly what they signed up for. Shaid Hussain emailed me to say that he has been overcharged by his photocopy supplier for the past seven years.

When he contacted the company to complain he was told that their terms and conditions stipulate a minimum of 1,000 copies a month or there would be a usage charge. "Our average use is 300 copies a month," he writes.

The company also informed him that he had signed a new contract in 2007 valid till 2012. "Should I wish to cancel, I must pay for the remaining duration."

His advice to others know all this before you sign. I have no doubt that these charges are in the contract. And no, the rep won't necessarily point this out. He's probably on commission.