Two part question...

we want to post ads on craigslist.org by automation... rather than a human posting these items for sale ads manually.
Anyone program such a thing?

We need some tips for our pc settings for posting ads in Craigslist.org
We think craigslist must be tracking our ip because when we post ads in their items for sale section, our ad never goes up. It is immediately "deleted". [within 1 second]

We are trying to use craigslist to post 1 item for sale ad in 1 city but... we have many ads to post each day across north america.

Here's what we've tried:

proxy ip
new craigslist accounts
different browsers like chrome, ie, firefox
delete cookies
incognito
but we can't get the ad to stay up. we are not spamming. we only place 1 ad in only 1 city. we never re-post.

If someone has had success at posting 1 ad in 1 city and then a completely different ad in a different city, etc etc. we'd love to know how to set our pc to have our ads stay up.