You can block calls made with a hidden number with the forwarding that can be done from mobile phones. Hidden number is no longer a problem anymore. You can block calls from hidden numbers with a few actions on your mobile phone. The GSM operator you are connected to will answer you by voice and inform you that you cannot be called from the hidden number. Thus, those who want to call you with a hidden number will be blocked. After this process, a message will be sent to the subscribers who call you by hiding their number, from the GSM operator they are connected to (You cannot make a call because you have hidden your number). Unless the relevant subscriber cancels the hiding process, they will not be able to call you.