publishing mobile users’ directory

I believe that publishing mobile users’ directory should be mandatory in contrast with the mobile service providers’ claim that it would lead to mobile spamming. Such a claim is useless and even after having opted to be in the no call list i get hundreds of advertizing calls coming to my phone everyday. so I believe there could be two reasons why the MSP dont wanna make the directory one, it would prevent them illegally selling the mobile numbers two they would be forced to keep the no call list a true one.