They are not MISSING. This has been explained many times on this thread and on the main site.
BA put them away in a safe place for you.
My Avios aren't either missing. My balance is 0 though, I'd like my 90k Avios back.
ETA: I call BA in HK, after 5 minutes on they picked up. The kind lady said that my account is under audit, but she doesn't know why. She sent a message to somebody & they will reply to my email at some point - hopefully as soon as possible.