After looking at their website & with a small amount of guesswork, could I suggest it might be something to do with Telecoms.
Maybe Business Landline services, Mobile & Wireless, Telephone Systems or Data & Networks !?
If you're
not a business or you're
not interested, give them a call on
0800 0838000
or
0800 2986725
and waste their time & money telling them what to do with their service !
And while you're at it, what to do with their 0870 number they wanted you to reply on !!
Also don't forget to advise them you'll be contacting the
TPS and then do it !