Hey tpmoney85, that's super strange! Clearly you need the phone to work while you're travelling. When I review the map for Spain on our Roaming Abroad page, it does look like the LG G4 should be able to pick up talk and 2G data in Spain. Are you using a T-Mobile LG G4? Can you check your settings against these: Network, APN, & VoLTE: LG G4? Are you having any trouble with texts or picture messages?
Hey again - just wanted to see if you're still experiencing the same issues! How is everything going?