My internet using some sort of proxy?

Hello,
Recently I have problems concerning my internet IP address.
After running at test on Netalyzr I've found out that my IP is on spamhaus blacklist,
but it's not really my IP address, I think my internet service use some kind of proxy on my original IP.
The results from Netalyzr shows this line multiple times:
(I am not sure if I should put my IP address online so I removed it)

I don't know if it's a good idea to show my IP here so I will just call it, IP X and IP Y. (Explanation below)

In other words my ip address is X and for some reason there is some sort of proxy that hides or change my IP address to Y,
note that the two IP address are completely different from each other, there is no similarity whatsoever.

When I go to Whatismyip.com it shows my Y ip address.

My questions are,
why does it happen, why do I have "two different IPs"
I've tried to remove my X IP from spamhaus but it keep getting blocked again and again, the other IP isn't blocked by spamhaus.
Is there a way to remove it and is it known thing?

Thanks for the help !