I've had a very similar experience recently with a VLC-MAD-LHR return. BA rejected claim as they say the last sector (MAD-VLC) was still showing as open. I called IB in the UK and they said it was closed. I asked them to tell BA this and they said they had. Only I had a second BA claim rejected for the same reason.

Eventually, after almost a month and faxing my boarding pass to both the UK & Breman and asking @iberia_en and @british_airways on twitter to help the miles and tier points have been credited correctly. In fact I found the twitter teams very helpful. Especially @Iberia_en who direct messaged me saying when the miles would hit my account after talking to BA.

I was also told there was a bit of a backlog from all the re-routings following the snow distruption.

Good luck & keep trying. Eventually they wil credit.