So I have a partially flown J itinerary and the return was booked as SEA-HEL-LHR-AMS in I-class. It's a BA 125-ticket with BA flight numbers, but the first 2 segments are operated by AY. Problem is, AY ended their SEA-HEL route as of end of Aug (flight is in Oct). AY sent an email to that end stating it was rebooked, but checking either BA or AY shows the segments simply missing altogether. There's just a lonely LHR-AMS. Any online change attempts just error out.

The fix is really simple: SEA-LHR on BA. However, if I am reading the above document correctly, if the flight is more than 3 days out, it must be rebooked into the same class (not just same cabin); and there is no I-class available on that day (on any oneworld route). Will BA rebook into R or D class on the nonstop or am I screwed?

(I'm assuming this is a BA call, but maybe I'll need to call AY since they cancelled?)