Signed up with BT over it's competitors for the £100 reward card (with mastercard was it?), and everyone ive been in touch with so far has passed me around and said there's no record.
There are hundreds of customers complaining about this exact problem all over this site, and the broader Web.
I spoke to live chat, got passed to one email, they passed me to the host of the card company, and they said they had no record of a card for me and to get back in touch with BT. On and on the circus goes. Seems an awful lot like there was no intention of ever delivering on the introductory offer. Not exactly a strong first impression for a new BT customer.