It's really unfortunate that happened to you. A few things:
1. It's the weekend. No one is at AAMC headquarters.
2. Breathe. If it was everyone at your center, action will definitely be taken. If you check out the Sept 2 thread, you'll see a post by Ad2b. 5 other students will also have to retest due to power outage. Ad2b was advised 48hrs for contact. I would assume the same applies to your case.
3. You will likely be rescheduled to Sept 19, the make up date already set for those affected by the recent hurricane.
4. All medical schools will likely be alerted to the special make up date, and will probably accept the Sept 19 date as a valid score for this cycle.
5. You got halfway? You got a free look at the C/P and CARS section. If you're anything like the rest of us, you thought C/P was bonkers and CARS had a good variety. You have two weeks to finetune any weaknesses that were made apparent in regards to those sections.
6. Postponing for a short period means more time for practice FLs. Altius or NextStep is commonly recommended.
This may seem like a curse, but if you play your cards right, it can turn into a blessing. Next steps for you:
1. Monday: get back to the study prep grind. FL day, review FL day, review weaknesses day, break day. Rinse and repeat til new exam.
2. Monday morning: send email to AAMC alerting them of what exactly happened, ask for clarification on what will done. This is to protect you in terms of timely notification of the administering body.
3. Wait 48-72hrs from your test date for a reply. So Sat 8am means wait til Tuesday lunchtime at least. Take into account time zones.
4. No response by Tuesday dinner? Tweet at em might help. Call your test center and ask if they have an update.
Best of luck.