Can you repeat these steps as given below? I guess now you are missing step no 6.
Start the Cassandra-cli connected to your node.
Run the following:
Check whether everything is fine or not. If not then delete the files in your system keyspace folder except files like Schema*.*. Every time you start cassandra node, it will compare the value between the one in system keyspace and the one in you configuration file, if they're not equal, you'll get an error. And please don't forget to keep the backup before deletion if anything goes wrong.
Hope this will help you