There is so much of this invalid ticket debacle at the moment apparently! I had some flights on IB at beginning of June on a BA ticket which didn't credit. Last Wednesday I actually got through on the phone and agent told me to submit documents via a website that he gave me. Later that afternoon I also went via the chat option on the website. Tier points and avios were credited today. Not sure which option yielded the result, but I suspect it was the chat option. Good luck with your efforts