Commenting the following line will prevent the "thetime" command from existing:
PHP Code:
register_clcmd("say thetime", "sayTheTime", 0, "- displays current time")
PHP Code:
// register_clcmd("say thetime", "sayTheTime", 0, "- displays current time")
Also, make sure that you recompile the plugin and put the new timeleft.amxx in the plugins folder and then restart the server.
I've attached the plugin with the "thetime" command removed if you'd rather just download the new .amxx file (click "Get Plugin").