Whatsapp is end to end encrypted so not even they can see what people are saying. I would assume that their logic is, there's no point in giving information over if the police can't even read it. If the police got a court order, they could get the information, obviously they didn't. Don't forget, whatsapp is also fu**ing HUGE compared to any VPN seller. Obviously the police didn't have evidence that they were using whatsapp for illegal activities or else a court order would have been gotten in a few minutes. There is proof that people are using vpns for illegal activites so a court order would be very easy and why would the vpn company try to fight it and waste money?