I don't think the issue is from the Telco, but I may very well be wrong. The calls are always on the inter ring, and when the Caller ID displays anything, it is often times an internal extension. It is happening to at least 3 extensions, maybe more.
I don't understand, "is it behind a VM or are calls ringing in direct?" Please fogive my ignorance, I haven't been trained in this field, just the slightly related computer networking field.
Thanks,
