@ Confidential... Interesting, how did you come across that number? I have spent the last ten minutes looking on google and can't find any record of that number or any company based in Telford listed as Excel telecommunications, there are listings for Excel telecommunications (UK) Ltd but with no contact details at all. The two numbers that call me, as listed above, seem to be dead lines and the one you put in your note rings through to a fax line.
I am on Orange so that would tie in with what you said about them being a contractor but I'm still curious as to how you got that number...
Whoever these guys are, they are not doing their company name any good and I have no idea why they need to be so shady... What are they hiding?