I got this call this morning and I recognized it as an invalid area code.  I just want to know how someone can even make a call like this go through?  Any ideas?  And who is it calling such as where it originated from and is this a scam call.

I am getting up to 10 calls a day from this number even though it is supposed to be 'invalid' area code.

When I answer, there is no message, nada, just silence and then a hangup.  How do I get these people to stop calling me??