Mobile telephone network providers may set their own policy on how they deliver a PAC (Porting Authorisation Code) e.g. in writing by post or email, or over the phone. They are hardly 'retaining' the PAC by selecting a postal option instead of a speedier delivery.
If your brother wishes to complain to the body which regulates the industry then I point you to Ofcom...
http://www.ofcom.org.uk/



