Flight cancelled but being offered a downgrade with no refund
I’m due to be flying ORD-LHR-AMS on 8th July in CW/CE. Got notified earlier this week that the LHR-AMS flight has been cancelled on 9th July.
The next flight BA are offering has no CE seats remaining. I asked them whether they could get me onto a KLM flight instead, but they refused. I asked whether I would receive a refund if I agreed to fly in Y on the next BA flight but they have refused.
Do I have any rights with the cancellation being more than 14 days out or do I accept the downgrade for the final leg?
Thanks