Uhm...yeah VBuzzer:
Well to update that further, calling
user@vbuzzer.com rings the phone but usually gets one way audio, and lately even SIP URI incoming has been spotty.
If you check VBuzzer's forum you'll notice a few people complaining about this... so it's something happening on VBuzzer's end, and it's getting less likely VBuzzer will do something about it.
That said, depending on what you're trying to achieve, you maybe able to work round it!!!