A variety of services have recently been provided depending on highly developed networks and personal equipment. With these advances, connecting this equipment has become increasingly more complicated. Problems such as an increase in no-connection and determining the cause have become difficult in some cases because software is often updated to keep up with advancements in services or security. Telecom operators must understand the situation and act as quickly as possible when they receive customer enquiries. In this paper, we propose a method for analyzing and classifying customer enquiries that enables quick and efficient responses. This method is based upon a dependency parsing and co-occurrence technique to enable classification of a large amount of unstructured data into patterns because customer enquiries are generally stored as unstructured textual data.