I uploaded an object and now wanted to order it. But what if the printing goes wrong (because of too thin walls, for example)? What about the payment (I mean, the material, theoretically, is wasted, or isn't it?)? Thanks in advance!
Before it is printed it is manually checked for print-ability. From that point the printer takes responsibility. If they say it's printable, They will try to print it. Sometimes it does take multiple attempts. But if it is not printable, you get a voucher to try again, or you can request a refund.