charging of a bill before the handset is released

so I would like to sign up to id mobile and order the 13T. the problem is the handset is not in stock until 28/12/23.

if I apply for a contract now will I be charged for the month prior to the arrival of the phone? considering I will not have the phone for over a month, common sense dictates I should not be charged until its arrival where my contract can start properly.

the issue is the site wants payment directly and ID mobiles customer service chat (supposed human) is not helpful or clear about the any of the information I have requested. Just repeating the same stuff from a script and trying to rush me off the chat before I can even read an reply to messages

can someone please give me a clear cut answer?