Razer Phone 2 Not compatible with Number share?

Hello, my son recently got the TicWatch Pro Lte smartwatch and has enjoyed using the watch. But when I went to the Verizon store to activate the watch. All the other lines on my account besides the Razer Phone 2 (The line the watch needed to go onto). So we ended up on the phone with support because there might be something the store rep could not do. So, I was on the phone for 45 mins before the call just got disconnected. If anyone else has had a similar experience or any advice that would be greatly appreciated. Thank you for your time.