My ISP Sold Me Dirty IP Address, Should I Demand A Clean One

I recently purchased a dedicated server from a company I found on these forums. I have been very happy with the company, but the 2 IP's I have with the server are blacklisted in many places. I have been systematically trying to clean the address, but am starting to think that it may be a losing battle.

My ISP has offered

I have assigned to your account the following ip:

ip:216.144.227.125
sm:255.255.255.240

You can bind Exim to a secondary IP using the steps below:

a. Login to the server as root using SSH and open the file /etc/exim.conf in
your favorite Unix text editor.

b. Locate the section of the file that contains the following:

remote_smtp:
driver = smtp

c. Replace this section with the following modified version:

remote_smtp:
driver = smtp
interface = 216.144.227.125

d. Restart Exim

I don't know anything about this. Can someone please tell me if this is the best route. I don't want this to create any other issues for my email, like causing reverse DNS issues. If this will totally solve my problem, fine. If not, shouldn't I demand to have clean IP's assigned to my server, especially since the service is advertised as such?

my IP's 72.11.145.112 72.11.145.113