Abstract: Service development with high quality has been written into national strategy. It is especially important in e-commerce with customer oriented. The service quality directly determines the shopping experience of customers, thus influencing the success rate of transactions and ultimately influencing the development of online shopping market. However, online sellers continue to encounter several challenges. Among the total complaints in China in 2017, approximately 60.59% are related to online shopping. The poor product quality, the difficulty of returns and obtaining a refund, and false promotion are the most common consumer complaints, which significantly decrease the shopping experience quality of online consumers, and hinder the development of online market. Hence, it is necessary for online sellers to improve customer service quality. Yet, online sellers are usually those individual households, mom- and-pop stores, which are characterized by capital constraints. That is, it is only an armchair strategist for them to improve service quality.
In fact, customer shopping experience is a joint action of node enterprises in an e-commerce supply chain. In order to keep a booming development of e-commerce, it is necessary to build effective, efficient cooperation relationship between node enterprises in a supply chain. According to the public document of the State Council, named "Guidance on actively promoting innovation and application of supply chain", the supply chain finance (SCF) should serve the real economy. Clearly, it is an urgent problem to find the way to provide efficient financing channels through SCF, simultaneously, to improve service quality and benefit all parties.
Under this background, the "credit contract based on the sales target" is brought. It means that the supplier allows the retailer to delay in payments just if the sales meet a certain condition. Such way is good for retailers to ease the funding pressure and to increase investment on improving service. Considering the effect of service quality on market demand, the repurchase contract combined with "credit contracts based on the sales target" is designed, an e-commerce supply chain coordination decision model is built it to obtain the optimal operation strategy. The results show that, the optimal decisions are helpful to remit retailer's financial pressure, encourage more investment in service, and improve customers' shopping experience. What's more, it helps to achieve channel coordination with arbitrary profit splitting, which improves the operability of contracts and guarantees the effective of the coordination mechanism. The optimal ordering decisions, service quality level decisions, credit period and sales target decisions are obtained. These decisions can help managers make full use of SCF, meanwhile, improve customer experience and realize win-win. The results help to accelerate the innovative practice application of SCF in e-commerce supply chain.

Key words: service quality, customers' experience, capital constraints, contract design, coordination