Comcast users

Occasionally I get messages from people using Comcast.net as server. I am unable to respond as Comcast has blocked out my small local server tyrone-online.co.uk as a spam sender or some such. I am trying to get this fixed at this end but maybe Comcast.net users need to try and get tyrone-online.co.uk off the bad boy list. I don’t really know how these things work but I hope Comcast users can help. Sorry to inflict this on all – but I have no other way to contact the few comcast.net users.
Brian