Why can we not port a Google Fi number?

I am having a really poor experience with Xfinity in getting clear messages. Note that the customer service people have been really helpful but every time I chat with them I get new information that was not shared with me initially as a new customer, for Internet and Mobile.

1. After trying for 2 hours with Xfinity and Google customer service, they said that Google won't allow the Google Fi number to be transferred. So I wrote a note to Google to ask why. Today I am told that Xfinity does not allow Google FI number transfers.

2. I was also not sent 2 SIM at the same time. I was also not told that the billing starts within 7 days of placing an order even if my phone is not activated.

I am now canceling both mobile lines to stop the billing. And will order again for 1 line only by walking into a store.

The whole point is to try and get a package deal with Internet and Mobile. Since I can't port my current Google number, I am forced to apply for a new number with Xfinity.