I also sell 3D printed items and they did the exact same thing to my account. I just emailed them and they had me send pictures of my workspace and process to prove my items are "handmade" and my account was restored within 48 hours.
The fact that they closed my shop without pre-warning when I had sales along with pending orders really made me lose complete trust in them. Especially considering the endless Chinese products on there that are obviously not handmade.
If they had contacted me inquiring about my products before closing my shop, that would have been a different story but that is not what happened. I refuse to do business with reckless providers.
*Edit - It was the 3rd go around with their support before I started to get rude and pointed out a ton of Chinese products. By this time it was a week after they closed my shop and I was done with even trying with them.
If somebody's spent the time, money, and effort to create stuff and then put it on Etsy, it's pretty shitty to shut them down arbitrarily.
If they treat people like crap, they're going to get a lot of rude and angry support calls...