I'm still battling with BA for credit for a QR flight last June. It's rather annoying as it's the last leg of a LHR-DOH-DPS/SIN-DOH-LHR routing, and the other 3 sectors credited within days of flying. All one ticket, and only a quick transit through Doha.
I went through the BA website last year for claiming missing Avios/TP and received a response asking for more details which I promptly sent back, heard nothing and have subsequently chased.
It's getting a bit annoying now... being a lowly blue I can't imagine there is any practical way to escalate.