I have the issue with my agents. Currently I rely on the caller phonenumber so I don't ask phone numbers to customer but when I do it's not 100% reliable (not to say not reliable). Did you try gladia to see if you have better results? It's a french company, I saw a demo where it performed really good in recognizing phone numbers, emails, ... But it was a standalone demo, I don't know if you'll achieve similar results through vapi