There are thousands of applications floating on Google Play which can help you achieve this task on your Android smartphone, however, allow us to suggest the following one as if not one fo the best apps are Calls Blacklist by Vlad Lee and Call Blocker Free - Blacklist by NQ Mobile Security (NYSE: NQ)
These download are free and with basic configuration you'd be on your way to blocking everything from unwanted and blocked calls as well as SMS.
