Same situation here. Itinerary in early April was AUS-PHL-DUB and then LHR-AUS. As of this morning only AUS-PHL remained. I went through the online refund request after first cancelling what was left of the reservation. It took the refund request but it said it required manual review. I was able to specify flight cancellation as the reason in the request. We'll see what happens.
Messages popped up during the process which were apparently meant to discourage you from requesting a refund and to have you hold on to the credit for a future rebooking. Can't say that I blame them.