1. A method for constructing a billing statement from a plurality of detailed usage file (DUF) records relating to usage of an unbundled network element (UNE), the method comprising: (a) downloading a master file from an incumbent local exchange carrier (ILEC), wherein the master file contains routing information associating each of a respective plurality of telephone numbering plan addresses plus additional telephone number digits (NPA-NXX) with a corresponding geographically defined local access transport area (LATA); (b) downloading one or more telephone operator services (TOPS) assignment files, each TOPS assignment file including a list of one or more TOPS switches that are used for calls originating at a particular NPA-NXX; (c) generating an enhanced master file by using the one or more TOPS assignment files to edit the master file; (d) downloading a plurality of DUF records; (e) filtering the downloaded DUF records to thereby generate a set of enhanced DUF records; (f) downloading a rate table associating each of a plurality of end users with customer price plans; (g) extracting information about calls placed by each of a plurality of end users from the set of enhanced DUF records and the enhanced master file; and (h) applying the extracted information to the customer price plans in the rate table to generate a constructed billing statement that reflects usage of the UNE.