Thanks, folks. It's the front AC seats in ET we're trying to bag. We already selected the seats a couple of days ago, then the dreaded curtain moved back a row and we were moved back to row 14. We chose the A of the new AC pair (the C had gone) with the other in the row behind. Now the curtain has moved forward a row again, and I'm trying to secure the A of the pair (the same as we already requested).

I checked availability on flightstats.com, and there is general >9 availability, so by no means full.

I called EC and spoke to a helpful person who spoke to the web team, tried to delete and reallocate our seat requests, was unable to do so, then called the airport to request that they block our requested seats. She'll call back within the hour.