When you say "last September", do you mean September 2013, or September 2012? If you purchased and activated your iPad on or after September 1, 2013, then you should be able to download those apps for free from the iTunes Store. Sign in and find the apps and see if they don't indeed say "free". If not, and restarting the iPad doesn't change it, go here:
and follow the instructions to report the issue to the iTunes Store.
If you mean September of 2012, then you're not eligible for the free copies.