I do not have this phone but maybe under settings or phone, there might be an option for "calls". Under "calls" you can (if your phone has this option) put auto reject. You can block certain numbers or you can set it to where the phone automatically rejects withheld numbers (*67). I hope this helps as I am not sure because that is just how you block numbers in my phone (Samsung Solstice). You can also call your cell phone manufacturer, customer support, or even go online for more options or solutions.
Download a callBlocker App, it will definitely works some apps block both call and sms too.Net10 cell phone service how to block a persons number