RingCentral STUN Engineer?

Anyone with abilities to view traffic for the STUN servers able to message me off list? I have been going back and forth a couple of weeks now doing PCAPs with not only RingCentral but with Palo Alto on the phone as well showing there is no return traffic coming from the RC side on call initiations and reviewing our configurations continually showing the traffic is allowed on our side. We created explicit in and out rules to define all traffic and no change. I'm stuck in tier 3 (they have been good though) and they are timid to escalate up to the STUN engineers to verify but I can't keep doing the same 'its not us' test with them when it is work impacting. Thanks in advance!