I bought baggage allowance for my roundtrip but it didn’t show on the airline checkin. My airline suggested I have to contact trip.com. After chatting with agent, she couldn’t fix it. So her manager called and claimed that the additional baggage allowance applied to my return flight even though the fee applied on the round trip booking. She said her IT department will investigate it to see if she could reimburse my extra fee paid directly to the airline. This is a huge hassle for my flight. The system wasn’t reliable and customer service took a long time. Not impressed!!