It looks like you succeeded at posting a reply last night. Did anything strange or special seem to happen, or was it all routine? Please update us on developments like this over at the Help Desk so that we are working with current status information.
Another new member recently had the same problem posting a reply. The system thought he was including a link, and as an anti-spam measure, links are not allowed for new members. You will graduate from that category soon, so you will be OK. But the underlying problem needs to be fixed, and we have reported the issue to the site management. We'll keep you updated.
As for the trailer plug situation, all that's left is to see what the dealer has to say. It sure looks like you have covered the bases.