Well, you could complain
If what I stated was the situation, then the only way is to buy a static address so it wouldn't change, other then that you can't do anything.
There's no point to paid extra just for a static address you probably would never use to host any server.
If you wanted to find out if your address keeps changing daily all you have to do is go to
www.whatismyip.com and write down the IP address. When it happens again repeat the process and compare it. You'll have a new address all the time.