haylefarm

Flew London to Bali last month on Malaysia business class. Entered my BAEC number when managing the booking. BA have now credited 200 TP's for the flight out, but not for the flight back. Malaysia without my involvement assigned their own frequent flyer number which appeared on all their emails but I ignored this as I had input my BAEC number for the booking and have seen other One World (e..g, AA) do this as well. Malaysia printed the flight out boarding pass with the BAEC number, but for some reason, and without my involvement or agreement then put their FF number on the return boarding pass. I don't see why they should be able to do this - I put the BAEC number in for the booking, i.e., both flights. I don't recall any opportunity or way to change the FF number for the flight back or why I would need to do that. I read you can transfer Avios but not tier points from partner airlines- which is especially disappointing as the tier points are why I flew Malaysia this trip. Are the 200 TP's a write off? How to avoid this next time? I keep missing Gold by a handful of tier points - so not very happy with this outcome!

LTN Phobia

First thing to check here is if the fare class is qualifying on BAEC. If not, nothing has been lost through MH assigning their own FF number (in fact it could even be seen as a gain) because you will have got nothing on BAEC anyway.

bisonrav

I assume you picked the second set of BPs (for the way home) at the airport in Bali?

It's not beyond the realms of possibility that someone has nicked your PNR and surname, maybe from a baggage tag, and inserted another FF number in between flights. Either way, if it's not your account, it shouldn't be on the booking. Did you retain the BPs with the FF number? I would be on the phone to MH pronto to ask what has happened.