Dear, we provide the test video before the device is shipped, you just need to add essential oil to test. It's not that the device doesn't work, you need to do it the right way. We have been actively working on logistic issues and solutions for you, but they have been rejected by you, I hope we are working as equals and communicating efficiently. For customised products, we have produced all of them, during the production process you want a refund, this is unacceptable, we have invested 100% of the material cost, the value is up to $12,000, and you only paid 30% of the purchase price, a refund is a huge loss for us. When we proposed solutions, they were all rejected by you. You did not see our efforts in this order and gave us a bad review, which made us feel frustrated and sad and heartbroken about this order. We hope that if we have the chance to work together again in the future, we will continue to provide you with first-class products and the best service.