Regarding the recovery of my phone number

I lost my old phone last week and I am unable to login to razer cortex to change my phone number. I had logged in from google and facebook but I cannot change my phone number from 630905224 to 7306095411. Everytime I try to change it, it asks for a 2 step authentication code that is sent to my lost phone; therefore I am unable to enter it. I tried to get my backup codes but again it sends the code to my lost device. Is there any way I can change my old number and update it to my new number? Please do help me out ASAP. Thank you.