Behind NAT - what can I do?

Here's the situation:

My ISP is part of a HOA and provides a cable modem/router, I have the latest airport extreme with WiFi set up

I installed a wireless video surveillance camera that works great locally, but of course I need specific ports for remote access to view. I did the port forwarding as per their manual but the ISPs router is behind NAT and they told me the only way I can set this up is with a static IP and they can't/don't provide this service in my area.

I show no open ports when I use canyouseeme.org on the external IP but do see the external IP address.

I read about NAT, but it's way over my head and I haven't a clue, although I got the inpression there are ways around it to accomplish what I'm trying to do. My ISP is part of the HOA fees I pay so I can't switch to another provider without still paying the current ISP.

I'm sure this issue is not unique to me, has anyone else experienced this sort of problem, and is there a reasonable solution?

All thoughts/suggestions will be appreciated.

Cy