[Konstantinos]

The ZCMD commands should not be inside any callbacks. You have to use or strcmp or ZCMD. Choose on of them.

pawn Код:

// I guess this is your code
public OnPlayerCommandText(playerid, cmdtext[])
{
    if(strcmp(cmdtext, "/despawned", true) == 0)
    {
        currentveh = GetPlayerVehicleID(playerid);
        DestroyVehicle(currentveh);
        SendClientMessage(playerid, COLOR_MESSAGGI,"[Acmd:] Hai eliminato questo veicolo");
        return 1;
    }
    
    COMMAND:me(playerid, params[])
    {
        new
            string[ 128 ], Name[ MAX_PLAYER_NAME ];
            
        GetPlayerName(playerid, Name, sizeof(Name));
        if(isnull(params)) return SendClientMessage(playerid, COLOR, "Usage: /me <Text>");
        format(string, sizeof(string), "*%s %s", Name, params);
        return SendClientMessageToAll(0xFF00FFFF, string);
    }
    return 0;
}

This is wrong. The commands with ZCMD out of any Callback and don't use OnPlayerCommandText Callback.