We check every product before sending and pack it carefully. We understand that sending it back in case of a defect does not make sense, as the shipping cost may be the same as the product price.
Sometimes a package is opened at customs and small parts (like bolts and nuts) can be lost. Sometimes a package can be damaged. We are not responsible for that, but we try to solve the problem ourselves.
If something is wrong with the order, we solve the problem: resend the product, return the money or send additional parts.