[Nonameman]

Return 0 after the condition that checks the admin level, it will prevent players from spawning.

pawn Code:

case 27 .. 31: {
     if (adminlevel >= 3)
     {
          SetPlayerPos(playerid, 1220.1063,-1410.3185,13.1395);
          SetPlayerFacingAngle(playerid, 354.7488);
          SetPlayerCameraPos(playerid, 1220.2598,-1407.5026,13.1717);
          SetPlayerCameraLookAt(playerid, 1220.1063,-1410.3185,13.1395);
          GameTextForPlayer(playerid, "~n~~n~~n~~n~~n~~n~~n~~n~~n~~h~~h~~p~Loco ~g~Syndicato", 3000, 3);
     }
     else
     {
          SendClientMessage(playerid, 0xFFFFFFFF, "You can't choose this class, it's only for lvl3 admins!");
          return 0;
     }
     break;
}