For the paper art prints and illustration originals: Not returnable and non-refundable, unless major damage has occurred to the print(s) during transporting. If you haven't received your prints, check your shipping/Paypal emails, they contain a tracking number.
For the products fulfilled by Society6 (e.g. tapestries): Non-returnable and non-refundable. Other products (e.g. t-shirts, pillows etc), bought directly on third party sites, are governed by their terms & conditions.