1) Carpets don’t cost 2.8K.
2) Go to the complex and ask why they are asking for 2K. Ask for a formal letter explaining the change, and a detailed bill.
3) If the changes are still not justified then talk to an attorney. - Perhaps you can make some money by suing them (apartment complex are rich and have money).  Finally, If you know/can find two other people who also received similar bills then I think you have a case for a class action.... A lot of money – in short many people vs. one company with same/similar complaint – a good chance to win.