Hi h, (sorry I don't know your name)
I was able to find the podcast following your instructions 1-6. Having located the podcast the only option available to me was to 'subscribe', not 'unsubscribe' as I'd hoped. I hit 'subscribe' then quit out of itunes and rebooted my iphone. In itunes the podcast was still not showing as being in my device's library, though on my iphone it was still there listed under 'My Podcasts'. I then followed your steps 1-6 again thinking that - having 'deliberately' subscribed - the unsubscribed option would be available Not so, the 'subscribe' option was available even though my iphone (but not itunes) already has it listed!
I then hit the podcast's subscribe button and it flipped to unsubscribe - which I did - and rebooted my iphone once more. The podcast is still on my iphone.
No doubt it will turn out to be something simple but it's pretty irritating at the moment!
Regards
Paul