How to lose your baggage _A|_ fly the F-U skies

My wife and I were traveling from South Africa to the US and she took a side trip to Peru. South African Airways failed to load our suitcases in Johannesburg and United who handle baggage for them in the US managed to deliver mine but lost hers en route to her in Peru (last recorded in Lima, apparently didn't make it to Cusco).<br> <br> 5 days into tracking the suitcase when compensation was due, they suddenly decided it wasn't their problem and gave me a new SAA file reference number and told me not to submit a compensation claim.<br> <br> I don't see why it is not their problem because they routed it to Lima via Houston on one of THEIR flights so they clearly lost it. It seems UA is happy to make money out of servicing SAA baggage until they lose something. Whatever their contractual arrangement with SAA, it is actually UA who lost the suitcase. Now I am left with a mess of phoning SAA in South Africa and trying to persuade my travel insurer they should cover this loss, which the airline should have covered.<br> <br> \Fly the friendly skies"? From United"