When a customer finds that what she or he bought is faulty or in some other way does not line up to what the producer promises ,the first step is to give the warranty(保单) ,or any other records which might help, to the store where he or she bought the thing. In most eases, this action will produce results. However, if it does not, there are various methods the customer may use to satisfaction. A simple and common method used by many customers is to complain(投诉) directly to the store manager. In general, the' the higher up' the customer takes his or her complaint, the faster he or she can expect it to do settle d. In such a case, it is usually settled in customer's favor, thinking what he or. she complains is just. Customers should complain in person whenever possible, but if they cannot get to the store, it is acceptable to phone or write the complaint in a letter. Complaining is usually most effective when it is done politely but firmly, and especially when the customer can show what is wrong with the thing he or she bought in question. If this cannot be done, the customer will succeed best by giving clear information as to what is wrong, rather than by general statement. For example, 'The left speaker does net work at all and the sound coming out of the right one is unclear.' is better than' This stereo (立体声音响)does not work.' The store manager may advise the customer to write to the producer, ff so, the customer should de this, expressing the complaint as politely and firmly as possible. If a police complaint does not achieve the desired result, the customer can go a step farther. She or he can threaten to take the seller to court or report the seller to a private or public organization in charge of protecting customers'rights. When a customer finds that what he or she bought has a fault in it, the first thing he or she should do is to ______.