They wouldn’t let me activate a card with one. They wouldn’t even let me activate my card with a phone number that wasn’t the primary on a family plan.
I probably connected the number before their anti-voip policy was enacted. This is true in a number of places. They have no policy against using a voip number; they just hope you won't register one.
I might try a couple of things:
1. Call Capital One customer service and yell at them.
2. Go visit them in person somewhere and yell at them. Bring a phone that rings when they dial the number.
3. Register a carrier number with them, and then, behind Capital One's back, port that number to your Google Voice account.
> They wouldn’t let me activate a card with one.
You can activate a card by just going to the URL printed on the sticker attached to the card. No need to use any phone number.