Have you tried using a hair dryer to heat it and then gingerly bending it back to normal and holding it that way until it cools? Not sure if it will work but it's worth a shot before trying something more extreme. 

I have never had one either.

Fairly common on lesser quality kits, especially ones from Eastern European companies that use several flat panels to assemble the hull (left, right, bottom are separate pieces as opposed to Tamiya style kits that use a one piece lower hull "tub").

ICM, Eastern Express, Zvezda, Maquette, have had issues as have very older kits by Revell, Lindberg, etc.

Some solutions are to clamp the warped part to a board and try to use hot tap water (not boiling) to allow the part to go back to its intended form. Boiling water may cause it to melt even worse.

Sometimes contacting the manufacturer online, like in Revell's case, they will replace the warped part. I've not heard of Academy ever having issues, but I would contact the importer. They often will replace the part.