This is so unfair and the system is so messed up that you do not know what you are actually getting on a code share. This happened to me a few years back so I try and avoid code shares. This year I did do three code shares through AC but I called AC and then TP and then LH to confirm the codes and then I had to fight for them. So I no longer do that.

For January I will fly ZX and not AC and I will do more of these as like you I do not want to pay extra and get nothing for it.

Lots of threads here about this, it's done you can appeal but I have never heard anyone win, but good luck as they need to know.