Apple Podcasts - https://podcastsconnect.apple.com/contact-us
Google Podcasts - apps-help@google.com
Castro -
Downcast - support@downcastapp.com
Overcast - feedback@overcast.fm
Pocket Casts - support@pocketcasts.com
Podcast Addict - support@podcastaddict.com
Podcast Republic - tech@podcastrepublic.net
Podkicker - support@player.fm
Rss Radio - support@dorada.co.uk