Hello, thank you for your rencezi, I am sorry to hear about your bad experience with the headphones. As for the replacement filters, they protect the headphones against dirt. If the headphones are exposed to dust, grease, etc., it is natural for the filter to become clogged. It's his function. Depending on the level of impurities, the time when the filter needs to be replaced is individual. It's not a manufacturing defect. However, replacement filters are usually included in the package. Just write to the manufacturer at
[email protected], they also offer replacement filters and always try to sort everything out to the customers satisfaction. Thank you and have a nice day, Ondřej - Alza expert