icloud.com / me.com silent discarding legitimate activation emails

I am he head of infrastrcture at tapatalk.com, a large social network based on forum users and forum content. We have hundreds of new users each hour, all of which require email activation. We don't have any problems with any email addresses junking our activation emails other than icloud.com / me.com addresses. Activation emails to these addresses are silently bin by Apple. All SPF / DKIM settings are correct, validated and verified as functional and working but Apple are still silently discarding email activation requests.

My question is who can I contact at Apple to discuss what we and Apple can do to stop these emails being discarded? We are currently having to manually activate accounts after support tickets are raised, causing more problems as they are raised from icloud.com / me.com addresses meaning that users are not getting their support updates.

Thanks