[Larceny]

Edit: /\

You are not getting player's name.

pawn Код:

CMD:ad(playerid,params[])
{
    new sendername[MAX_PLAYER_NAME], string[28];
    GetPlayerName(playerid, sendername, MAX_PLAYER_NAME);//<<<<<
    format(string, sizeof(string),"ADVERTIESMENT: %s, contact %s (ID:%d)",params,sendername,playerid);
    SendClientMessageToAll(COLOR_ORANGE,string);
    return 1;
}

Obs. Your string array is too short, will not print all characters.