Need to change admin portal username/Email ID

I recently joined this site, in mid-july, but I cannot find a way to pay the invoice using the app. Is there an email I can write to regarding this issue?

Hi, For the last few months, I could not contact booking.com with any mobile phone : the bip option doesn't wok (press 1 or 2 ou 3...). I Tried with an Iphone

Hi I would like to customise the name of my rooms and can't find out how to do this? THanks