Contacting mail admin of pocca.com is the right way to solve this issue. It looks like network related issue, e.g. Network firewall, dns cache (on their side), etc. If all above are correct, your mail server will log something.
So I suggest you waiting for some time and working together with poccam.com admin.
Thanks very much for purchasing our remote support, and i refunded your payment since there's nothing i can do for you for this case.