Any quality problem occurs when using the machine; we suggest you to seek help from the maintenance worker first. If not meet your demand, please contact us or the dealer. We will arrange serviceman to deal with it as soon as possible. As usual, we will arrive the expected place within 48 hours where there has our office nearby, and within 72 hours where there hasnt our office. For the out of way place or inconvenient transportation rigion, you can negotiate with us to make a final decision. Within 15 days after the machines are bought and used, under the circumstances of the damaging occured in some spare parts of the machine with serious problem of knitting quality that could not be solved after maintained by our company, the customers can ask dealer or company for changing a new machine after identified by the authorized service institution of our company. If the original needle bed has some wounded, the machine can be replaced a new one with some fees.