There is an email address listed towards the end of this page, though the response may depend on the nature of your query. A few years back but I was forced to deal through their online chat & ticketing system to reclaim an over-charge. Email or phone contacts said they couldn't assist. Took 6 months to sort that one.
Had a difficult time contacting Aer Lingus last year when my flight was cancelled. WhatsApp chat, messenger facebook email - kept being told my complaint was being processed and they would contact me. Finally I registered the complaint with IAA - within 10 days my flight cost & compensation was paid.