i am not sure if it someone using skype or a calling card but mine situation is similar
 Dec 03rd, 2007
This caller keeps calling and hanging up. Not sure if its a business or prnk calls but seems to be unlisted. most calls come thru as a private number but twice now these calls have come thru with this number and it is the same type of call. I f I call the number back it seems to be 'unavailable' for hrs.
 Nov 28th, 2007