Stop Pesky Phone Stalkers

(1) Call and SMS Easy Blocker
This free app from KAISARs Lab is very efficient for completely blocking calls and texts from selected numbers. What is even better about this app is that you won't even be alerted about the calls and texts arriving. There is a catch though; the free version only works for five unique numbers.

(2) Caller ID & Block Calls, Texts
This app from Phone Warrior Inc takes avoiding stalkers to a new level. What's more annoying for stalkers to have their calls picked up and then dropped ten seconds later without hearing anything from the other side? Yes, this app lets you kill off phone credit from the blocked numbers and also has the option of sending blocked calls over to voice mail, if that is something you would prefer.

(3) Call Blacklist
If you prefer that no number that isn't already in your phonebook can reach you, then Vlad Lee's Call Blacklist can help. It can block all private numbers (such as the obscure numbers stalkers or fraud groups sometimes use) too. However, the unknown number blocking feature does not work on all phones so the model of Android you are using will matter.
There are a quite a few other apps that can do the job equally well since it's a simple enough function. McAfee Anti-Virus, for example, comes loaded with a call-blocking feature in its extras. As it is, don't let someone bully you into changing your number. A few simple and easy to use apps can easily solve the problem.