[LegacyCode]

Try this:

PHP Code:

#include <amxmodx>

public plugin_init()
{
    register_plugin( "ChatCmdBlocker", "0.1", "LegacyCode" )

    register_clcmd( "say", "handleBlockCmdOutput" )
    register_clcmd( "say_team", "handleBlockCmdOutput" )
}

public handleBlockCmdOutput( id )
{
    new const a_ChatCommands[][] =
    {
        "thetime",
        "/rank",
        "/top15",
        "/hp",
        "/nextmap",
        "/timeleft"
    }

    new s_Message[192], s_ChatCmd[16]
    read_args( s_Message, charsmax( s_Message ) )
    remove_quotes( s_Message )
    trim( s_Message )

    if ( !s_Message[0] || !is_user_connected( id ) )
        return PLUGIN_HANDLED

    copyc( s_ChatCmd, charsmax( s_ChatCmd ), s_Message, ' ' )

    for ( new i; i < sizeof a_ChatCommands; i++ )
    {
        if ( equali( s_ChatCmd, a_ChatCommands[i] ) )
            return PLUGIN_HANDLED
    }

    return PLUGIN_CONTINUE
} 


Place it at the very start of the "Custom" section in plugins.ini:

; Custom - Add 3rd party plugins here
block_chat.amxx
...

I hope this is a good attempt at the problem, I'm new to this.
Let me know if it works!

- LegacyCode