Yes
No they have no way of knowing.
You can't do this without a Twitter account.
No, the only thing that will happen is that certain tweets will be sent to you as a text.
Go to mentions / THE @ Sing
Type @username into the search function to view all tweets sent to that user.
You can do a search for tweets sent to someone by typing @username (replaced with their actual username) into the search field.
You're either not using the correct username or they have blocked you.
One cant edit a sent inbox message on Facebook. One simply has to send an edited message and explain where the error came from. Facebook doesn't have a way to edit a sent inbox message as of yet.
Tweets. Private messages are called Direct Messages or DM for short.
no
The site wold have sent you an email and with that link you should be able to edit your ad.