Since we moved offices (same building - next door), my RingCentral phone has been getting constant and repeated phantom calls from the same number that shows "3=3..." in the Call Display. My assistant has also had weird calls like this in the past, so just wondering what these are and why do we get them if they don't have meaningful caller ID's? And how do we stop them!? We are in Canada.
This is a worldwide scourge and there is nothing in particular RingCentral or you can do about it, unfortunately. You can read about US legislation around the STIR/SHAKEN protocols that are being touted as a possible solution. Another possible solution is that "normal" phone calling will just die away to be replaced with things like What'sApp etc because people will get so annoyed they will stop using regular phone numbers.
Sounds like a SipVicious attack (Port scanning on SIP ports). Have your IT consultant tighten up your firewall and to only open the RingCentral ports for their IP address ranges. You can confirm this by checking the Call logs....if these calls aren't there than most likely SipVicious attack.