Community Health Network Indianapolis, IN Community Health Network Already paid my bill, but the company still wants that amount. Indianapolis, Indiana

I have already paid my bill to Community Health Network. I went to their physical therapy office in May and up to June 2009. I decided to stop going since I have little money, and these greedy crooks were charging me around $500 after my insurance would not pay for my physical therapy treatment. I hate Indiana people! So d**n greedy! Anyhow, I already paid my outstanding billing statement balance three weeks ago with my credit card.  However, just two days ago, I received another billing statement asking for the same amount I have already paid! Uggh! I'm just totally peeved and angry at Community Health Network that they would charge me a rip-off price for only three stupid physical therapy visits, and after paying off all the balance, they still want MORE money! So corrupt!