Hello everyone! I'm having trouble giving Vapi a phone number.. We're trying to use our telephone system, which has the SIP-Trunk with our phone number block, with Vapi as a client. Is this even feasible? I was under the impression I could use our system as a gateway since registering Vapi directly with our provider is not really possible. I've read too much and am just confusing myself at this point, would appreciate any help!