I had booked 4 one way tickets , two adults and two kids (even though was infant 20 months)ticket from SFO to BOM via FRA , We missed my connection from FRA to BOM and were rebooked on air-india flight FRA to DEL to BOM , but we just had 2 adults 1 kid and 1 infant ticket from FRA to DEL and BOM even though I paid for kid ticket , is there a way to get a partical refund and what is the path of least resistance

I did email customer relations at lufthansa , no response from them