Charged for unusable app, doesn't show up in askforarefund

I purchased the Headspace App through the app store. It stopped allowing me to access content about six months ago. I filed a ticket with Headspace, and they let me know they couldn't solve the issue because the subscription had been purchased through the app store. So, I've paid $94 for a subscription I cannot use. When I use the "askforarefund" tool in the support section, it only shows subscriptions purchased in the last month, such as Apple Music. I would like to be refunded for the app that doesn't work. Any ideas?