I redeemed United miles for a flight from Argentina to the US, with the first two legs on Copa. I was just denied boarding by Copa Airlines because they said United improperly ticketed my lap infant and Copa said they were unable to issue a boarding pass for my lap infant.

When I booked the flight on United, I immediately called Copa and tried to reserve seats. Copa said the lap infant ticket wasn't issued properly, So I've called United 3 times over the past two months first to fix the lap infant ticket issue error, then to later confirm that the ticketing was proper, with United saying they called Copa to confirm. We arrived 4 hours before departure and despite the Copa supervisor at departures talking on my phone with the United reservations supervisor, and United reticketing the flight, the Copa supervisor said it was still improperly ticketed and they didn't resolve it before the flight left.

I'm on hold with United getting rebooked on a later flight for tomorrow, but I'm wondering if there's any benefit that would help with staying in a hotel, meals, etc. I paid using Chase Sapphire Reserve, would trip interruption insurance cover me due to carrier error? Would United cover the cost of a hotel room and meals? How would I even ask for this?