i can not open syncUp kids app in my phone

We just bought our son's syncup watch today. My husband can get into the app. I was able to accept the invitation. Then it went back to the startup screen on the app and won't do anything else. 

Also, is anyone else having issues placing calls from the watch? It just goes to the customer service number despite them working for over an hour to try to figure it out at the store... 

We're excited about the potential good this watch could be!... If it works...