How can Apple's mobile phone short number be hacked so that he can't get in after hacking the virtual short number?

That depends on whether you hacked a t a name or a batch of TAs. If your cornet and trombone are both in the same name, and the names you have blacked out are the same, then neither the trombone nor the trombone can be typed in. If you save these two numbers separately, you can lengthen the cornet and call it in.