Use the 'contact us' button at the bottom of any page, and ask admin about your ad.

LLAP,
Swim

going to "my posts" under the more drop down menu and seeing what it says.

It may have the reason why your ad didn't go up.

Also, have you thoroughly read the rules for posting ads in the TER user guide?   You may have something wrong like not having a TER logo on your site or similar situation.

that means their posts are reviewed before they go live.  After a bit... with a history of following the rules... you can request to be unmoderated.  If you break the rules, Moderation can be reapplied.  I don't think ads are any different.  
Moderation review can vary from hours to a day or more.  
Checking status is a good idea!