See, this is something you should have mentioned in the first post.
Like most things on your Arch system, it does not read your mind or try to configure things for you.
Your IP address must change for an update to be logged.
In order to keep your No-IP Free account active (even if your IP address has NOT changed), you must update your host every 30 days.
If you are using the Windows or Mac version of our Dynamic Update Client, be sure you have placed check marks beside the hosts you would like to keep updated.
If your using our Linux client, be sure you are only trying to update one host, or a GROUP of hosts (see the README. Updates are only done when your IP address changes, not when it is different from what the host is currently set to.
When my WAN IP changes, the DUC client quickly updates it in few minutes, and in my account on I can see that it is also refreshed properly.