I would call into the Court Service office of the relevant Court, show them the summons (but don't surrender it) and see what explanation they can offer.
It may be the case that AGS failed to lodge the served original in time. It may also be the case that someone in the Court Office made a boo boo in compiling the list. There may be other possible explanations that don't come to mind.
That being said, and if you're absolutely certain the mistake isn't yours, I would be seeking to have the matter struck out if it is ever re-entered to another date on the basis that you answered the summons in the first place and it wasn't dealt with.
If however the matter is of a semi or more serious nature and it is re-entered I would be consulting a solicitor if I were in your shoes.