If you no longer have the mobile number, but it is still on the account, you have to get the number back. There is nothing anyone can do if your account does not have the correct number on it. It is important to remember exactly how all of these devices are linked together. As you can see, if you do not handle your accounts corrrectly, then you loose them.
THERE IS NOTHING YOU CAN DO, BUT GET THAT OLD NUMBER BACK!