I have a missing bag and was wondering if you all can help me sort out with which airline I should be speaking.

I arrived AMS on Monday (routing DTW-ORD-LHR-AMS) and my bag did not show up. I went through the usual airport routine for missing baggage. All legs except LHR-AMS on AA, LHR-AMS on BA (AA codeshare). At AMS, BA's baggage operation is handled by Servisair.

At the airport, I filled out the form from Servisair to start the process of looking for a lost bag. Servisair printed me a form from BA saying that if my bag does not show up in 5 days, I should mail them a form, and that if I do not mail it to them within seven days, they have no liability.

After a day and a half of no baggage, I contacted Servisair to ask about the policy for getting reimbursed for things I need in the meantime. Servisair says to contact BA. No contact information is provided other than a mailing address, so I phone a general BA number. CSR says that they have no record of the bag, I started by journey on AA, it must be AA's fault, call AA. What about the form I'm supposed to mail? Doesn't apply, I'm told. My WorldTracer number is BA? "That must be something Servisair did. BA is not your contracting carrier."

I call AA's baggage number. They say that because the last leg was on BA, they aren't responsible. CSR, very proud of herself, says "at least I was able to find your ticket in the computer." Tells me to call BA.

So... yeah. I'm a bit confused and frustrated that neither airline is stepping up to say "here's what we're doing, here's what you need to do." If anyone has any advice on getting this sorted out, I'd appreciate it.