Phone number changed

So I got a new phone number and I changed all my accounts 2FA before i start using my new number YET I FORGOT RAZER CENTRAL / ID so then i got back i was able to log back into my account because it didn't ask me for a code but I was trying to change my phone number to my new one but then it asks me for a code the old phone number is unavailable anymore what can I do to change my old number to my new one???