OMRON Nebulizer Malfunctioned and Warranty Claim Was Denied

I purchased an OMRON nebulizer, and the part where the mist comes out became punctured on its own, causing the device to malfunction. Since the product was still under warranty, I sent it in for warranty service and provided a detailed description of all the problems. However, after approximately 20 days, the device was returned to me without any repairs or service, as if there were no issue with it, and I was told that the problem was caused by user error.

I do not accept being held responsible for a defect that occurred on its own or having a product that is still under warranty returned to me in such a careless manner. I request that the malfunction with my device be evaluated as a manufacturing or product-related defect rather than user error, that the device undergo a proper reinspection, and that it be repaired free of charge or replaced.