I know it's a  B!%#/  $i!!y  question, but I have to ask it every time.  
Where in Thomas Cook would you like to contact ?? I live nearby with contacts there so may stand half a chance if I knew where in the organisation you want !  

Update: Unable to find your 0870 but you should be able to find what you want from the following:-

Thomas Cook Ltd.	. . . .	Thomas Cook Ltd.
Head Office	. . . .	Faraway Holidays
Thomas Cook Business Pk	. . . .	Merlin Business Pk
Coningsby Road	. . . .	Coningsby Road
Bretton	. . . .	Bretton
Peterborough	. . . .	Peterborough
Cambs.  PE3 8SB	. . . .	Cambs.  PE3 8SB
Tel: 01733 417100	. . . .	Tel: 01733 417000

Also there is on Tel:

Good start    but . . .
I've looked carefully at the site & it gives NO more information. The layout suggests it is part of TC Retail, & not TC Direct. Half the tab links on the page point to . . . . the same page,    which is just a slight 'faux pas' by the web designer !! (0/-)

Now if YOU'd like to telephone the number and ask them what department they are, YOU can then tell us all 'cos at the moment we're in the dark.  

My wife used to work there and I'm afraid you've got her asking the same question as myself.

WHAT DEPARTMENT  ???