Im getting the IP of my ISP's cache engine!!

Ive installed my 512kb ADSL last december and after a very long time, Ive heard something about port forwarding (YEAH!!!), I've started hosting my own web/ftp sites and everything went fine. I've got a dynamic IP and use the Dyndns.org service to do the IP mapping. My IP changes approx. every 23 hours. 3 weeks back, Ive noticed that Im getting the same IP...(I thought I was a lucky guy). But my web/ftp sites cannot be accessed. I also use a P2P applicatio for some file sharing[mmm... files that can be legally shared... of course ], its not working anymore. I dont browse the net that much, nor download files from websites. I need only my P2P app and my website...but none is working. Maybe its time to talk to my ISP. They told me that the IP Im getting is the IP of the cache engine(...that they have newly installed). Thats all I can get from them.
Urmm... is there a way?

->Yo Tony.. Y dont u go 2 another ISP?

->No,I can't, because Im paying the price of a 128k intead of a 512k. I won't get that anywhere(...Im a bit cheap).

Thanks for any suggestions.

 

[FaiTHLeSS]

Sounds like dyndns.org is detecting your ISP transparent proxy. What do you use to connect to the internet? You should be able to get the correct IP from the device you use. Does your ISP offer static IPs? Also check that you are allowed to host servers on your connection as they might not allow it.