I hope they say they are the only ones that can supply "infinity" - which is technically true. People assume infinity = fibre - if they are saying they are the only ones with fibre then people told that can complain to ASA/Ofcom.
EDIT: The OP doesn't state why they believed only BT could supply and as someone else I think said it is possible TT can't currently provide as they may not yet have put their kit in the exchange.
EDIT2 : The OP does now state and I have responded to that additional info.
Edited by ian72 (Thu 26-Mar-15 15:55:11)