I'm sorry to learn of unwanted calls. Though we are unable to trace the number & provide you with information on it, you do have the ability to block the number using our Call and Message Blocking feature. You can block up to 5 numbers for free, for up to 90 days at a time. Check out the details here: http://bit.ly/17iJEFh
Thanks to ttipgem for the information on contacting the authorities in your area. This is also an option, if you would like to press charges instead of just blocking the number.
I hope this helps!
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There are various apps which can block incomming calls, and some of them are even saying that they can trace them. I'm not sure that it can be true, since even Verizon said it can't do it; However, blocking feature is simple and easy to use. Check http://smstrackers.com/ for more info