Lee I am merely telling you what I see in the code.
Your buyemail is stored in your classifieds user table
Content visible to verified customers only.
You can update that field on editing of an ad or uploading a new ad anytime you wish.
I can look at your site but the issue is not coming from the code. whatever information is displaying there has to be showing because you actually have it in there or some hack issue.
We are dealing with a straight this is the database value and edit and store a new value. Nothing too complicated there.