Chat to it, and call it, from inside the portal — no phone number needed.
Test your AI Assistant runs the same assistant your customers will get, using the same knowledge and the same instructions. Nothing you say here reaches a customer, and the conversations do not count towards your leads.
If the call button says voice is not switched on, that is a setting rather than a fault: turn voice on under Chat & Voice Settings and try again.
The phone icon inside the chat window is a separate setting — it is whether visitors to your website can talk instead of type. The Call button above the chat always works.
A test call uses the same voice minutes a real call would. A few minutes of testing is nothing against a monthly allowance, but a long session is worth knowing about.
Two places to look. If it invented a fact, it is missing from your knowledge base — add it. If it knew the fact but said it badly, that is the instructions, under Chat & Voice Settings.