phone number change

Hi!

here's my case:

i have logged out my account on my ipad and input the account of my girlfriend.

after checking some things, i decided to log in to my account. Unfortunately, before logging in we need a verification code. this code will be sent to a phone number i have provided in creating an appleID account (i know all this for a fact)

my concern is, THE phone number i provided (which will receive the verification code needed to log in) is already INACTIVATED (that is, the sim card is already busted) and i forgot to change it before logging out my own appleID account (my bad, sorry)

now i cannot use my own account because of this. i have no other gadget (phone/pad/pod/MAC). i only got this ipad.

what can/should i do to change that inactivated phone number? the system is always sending verification code to that busted number, to the point that the system is not giving me anymore codes!

appreciate who will help

THANKS!