A note from BT's Legal Department:
'BT takes all allegations of misrepresentation very seriously and has recently received an undertaking and payment of costs from at least one competitor to desist from misusing the BT name and brand and passing themselves off as BT.
We would like to urge any forum users who are approached by companies misrepresenting their relationship with BT, to report these incidents either to their sales channel or to the following mail box - email@example.com. BT will not respond to the email, but we may use the information provided to contact you for further information and also to complain to the company concerned and the telecoms regulator Ofcom.'
As an aside, if you receive calls like this you may wish to consider signing up to the Telephone Preference Service, which enables you to request not to receive unsolicited sales and marketing telephone calls to your landline telephone number. You can register online, call the automated helpline on 0845 07 00 707, or write to:
Telephone Preference Service
1, Oxenden Street