It is against copyright to use or copy or distribute an artistic work. Since you are designer of your own product therefore in case of exact similarity with original work it would be considered violation of the copyright, intellectual property right at your own risk. You are requested to use your own artistic work (paintings or drawings or photographs or designs) for your product. The company will not be responsible for conflicts on intellectual property rights for using external designs.
The design selected by you is an overview of colors on the website and it may differ once printed physically on the garment.
The return of a sold product would only be possible in case of defects or damage or wrong size.