The stream title not changing is a commonly heard issue. This is because SHOUTcast uses the info in their database instead of the one you provide once you set it to public. It is easy to fix in two steps:
Check your mount point configuration. Under the “AutoDJ” tab there often still is the old title.
Check your Authhash: when SHOUTcast v2 is set to public the stream title is frozen unless changed in the Administrator part. Just log in and press “Update Authhash”. There you can edit the name and save it.