A friend of mine who is a contact in my phone, says he keeps trying to call me, but just gets a funny ring, and then nothing. No voicemail comes on or anything, and it does not ring in on my end, nor do I get a "missed call". This is the only person who says they are unable to get through to my phone from his. I have no problems getting through to his phone when I call. Why would 1 person be having issues calling my phone & not ringing through?
This sounds like a switching issue. What would need to be determined is if it is related to you line of service or to the originators line of service. From what you have described it doesn't seem like your having any issues with inbound or outbound calls.