They don't (well, very rarely) delete posts.
It looks like you're talking about your for sale thread.
As a Gold member, you can do a few things. You've already changed the title, you can also go back and edit out the contents of the post. You can erase it all if you want or just put WITHDRAWN to show it's no longer for sale and then close the thread. (by clicking thread tools in the upper right above the first post)
A few things to note regarding sales ads:
1. It is not that wise to put your email address right there in your sales threads. A person does not need to be registered on BladeForums to view threads on the Exchange, so anyone just passing by can stumble upon your thread and contact you when your email is present. Sure, we are mostly strangers here too but it is better to keep it so you are only contacted by folks that have an interest in the forum and those that you can vet, be it by previous sales history, posts, and other interactions on the forum. Scammers are everywhere and this is just one more way to help protect yourself.
2. While this most likely isn't your intention, but what some people do to skirt the 14 day repost rule is edit out their threads completely or put withdrawn and then repost the same item within the 14 days. It may feel like you (not you, a general "you") beat the system, but the mods can see all edits made and will know what's going on. So just keep in mind that it is still required to wait 14 days to repost an item withdrawn or taken down.
3. If you still want to sell it, then don't be discouraged that it hasn't been picked up yet. It is quite the unique piece and not exactly cheap by most peoples standards so it will probably take a specific buyer to come along and purchase it. Also, money is generally a bit more tight around the holidays, which could be another reason why it is taking longer than anticipated to move.