You can change the Visibility of your Listings / Ads. Go to your Menu on the top right and select Listings
Then you can Edit a particular listing and make it hidden. Please look at the screenshot below to see how it looks after you do that.
You can delete your Listing or Ad but we do not recommend it. It is better to Hide it until you are ready. You can Edit and again make it Visible.
If you have any serious issue then you can reach out to us.