From the terms and conditions:

Seat purchase value is refundable in case of involuntary changes to your seat due to safety, security or operational reasons.

Maybe try calling another time pointing to the rules. In my case I bought seats that were on second deck a380 and there was aircraft change so instead of 2-3-2 configuration we were seating in 3-3-3. It took me almost 30 min on the hotline for them to make a claim and few days to process it.