These changes make MapleStory M from Sletrry's blog

Afterward, NexonNA simply needs to need this on all newly created reports. They also need to connect each telephone number to a specific account. If that account receives a ban, so will the telephone number. In this manner, once a bot account is banned, Maplestory M Meso will need a new phone number to make a new account. Phone numbers, while plentiful, are far far less plentiful than ip addresses are.

This places a huge barrier which only gets more effective over time (as an increasing number of telephone numbers are obstructed ) against bot accounts. But it does not hamper legitimate gamers in all (because, honestly, if you've got a computer which can run MS you've got access to a telephone of some sort ).

I know that there are some disadvantages, but I do not think they are big enough to justify not implementing this method. The biggest disadvantage I can see is that a bot/meso farmer uses buy Maple Mobile Mesos your phone number and has it banned until you attempt to produce your account.

 If that's the scenario, there might be a rather intensive approach to clear a phone number (it would need to be intensive to be a successful ban). Either that or you are out of luck, but the probability of that occurring anyway are slim to none to begin with.