what can happen if you stop the adhd med vyvanse 70mg. abruptly?

my son was put on this med app 5mo. ago while in a treatment center, it has helped tremendously. Problem the Dr. must write a new script each month, had that done took it to fill the insurance co. said it was too soon, earliest 05/03 but not due until 05/10. Med was filled & delivered to treatment center according to insurance & pharmacy on his release date on 04/10 after he had left the place @ 8:25 am,we were there @ 7:30am no one delivered during that time frame. The center said they either never received the med or it was sent with us, the only vyvanse we were given was dated for 03/18 (30 day supply) so now teh pharmacy here will not give to us until this is settled, which both places promised to resolve yesterday, @ 4:55 no one had called me back ,I got voicemail to both places when I called now its the weekend he has been out for 3 days so if settled mon.5 day no med.now we are in a panic waiting for some bad effect to take place withdrawals,seizure s so said the web now scared