new String:bannedtext[300];

public OnPluginStart()
{
     AddCommandListener(HookPlayerChat, "say");   
}

public OnMapStart()
{
    new String:Info[64];
    GetCurrentMap(Info, 64);
      
    new Handle:kv = CreateKeyValues(Info);
    Format(Info, sizeof(Info), "cfg/sourcemod/test.txt");
    if (!FileToKeyValues(kv, Info))
    {
    CloseHandle(kv);
    PrintToChatAll("Ошибка!");
    return;      
    }
      
    if (KvJumpToKey(kv, Info, false))
    {
       KvGetString(kv, "text", bannedtext, sizeof(bannedtext));
    }
}   

public Action:HookPlayerChat(client, const String:command[], args)   
{
     new String:buffer[512];
     GetCmdArg(1, buffer, sizeof(buffer));
       
     if (StrEqual(buffer, bannedtext))
     {
        PrintToChatAll("");
        return Plugin_Handled;
     }
}