static ip changed again

In my business plan, which includes in 5 static ips in order. But recently the 5 static ips cannot be used. Because the comcast cable modem's ip is none of the 5 static ips.

I have no idea to deal with it. Please help me.

 a couple of days ago, the the problem had been fixed.

 Recently I forgot my modem login password, then I resetted it. After that, the ip changed again.

So I need your help to fix it back.