When I ring a colleagues mobile phone from any of the phones in my business, it presents the CLI as the main SIP trunk number. However when I ring MY mobile phone from the same phones, it presents the correct caller ID (specified in the extension configuration on the 3CX). I have multiple businesses using the same system, so cannot have this happen. Why would there be such an inconsistency? My telco says it's not them, but I'm not sure. Would appreciate advice - thanks.