Carpet cleaning scam

There have been recent reports of a carpet company cold calling elderly and vulnerable residents in the Thames Valley area.
Since the beginning of November, Oxford Trading Standards have received 6 complaints from elderly residents who have been cold called by telephone by a carpet company who state they are in the area and offering to clean carpets for £19.99. Workers come and clean the carpet, but then issue a bill for anything between £300-700 and insist that this cost is paid. Please be aware of these cold calls and refuse the ‘service’ which they offer.
If you have received a phone call recently from a carpet company offering to clean your carpet for £19.99, or know of anyone who has (if possible check with any elderly neighbours) then please contact the Doorstep Crime Team at Oxfordshire Trading Standards on 0845 051 0845 (option 2), thank you.