Car broke down on highway

Need a little more information on your problem. Was the car running hot? Usually if the alternator belt brakes, the charging light or battery light will come on, the engine will run till the battery goes dead and then dies and won't start unless the battery is charged. Unless the same belt runs the water pump in this case it might have overheated causing severe engine damage, in any case you need to get a second opinion from another shop, sounds like some one may be trying sell you something you may not need. Thanks for using 2CarPros