A spokesperson said: "Our advice as always is never buy goods or services on the doorstep. In the case of a mattress there are concerns that despite possibly displaying Fire Safety labels, there is no guarantee that the mattress complies with the relevant Fire Safety Regulations. They may also be of inferior quality and grossly overpriced.
"Help to stop these traders by sharing this message with your family, friends and neighbours. Please report any incidents to us via the Citizens Advice Consumer Helpline on 03454 04 05 06 or Cumbria Police on 101."
For general advice on consumer issues you can visit www.adviceguide.org.uk