Can't delete or change account's phone number

Hi recently my account was hacked and i recovered it thanks to ea support but there is a problem with my account. In ea portal there is a linked phone number with my account(its not mine). When i try to delete or change it verification codes go to that number.  I mean there is no chance i can delete or change this number. Ea live chat said "we can't see any linked phone number with your account from our end". Check the screenshot please. Is it because they changed ea portal interface its kinda a bug?