Systems, methods, and apparatuses may include a Billing System (BS) node, Charging System (CS) node, and a mediation node for managing Mobile Station International Subscriber Directory Numbers (MSISDN)s for a telecommunication network. The system may make an MSISDN available for reassignment immediately or shortly after (e.g., seconds, minutes, days, or weeks after) receiving a cancellation request associated with the MSISDN. For instance, upon receiving the cancellation request, the system may store a line identifier with an association to the MSISDN and/or an International Mobile Subscriber Identity (IMSI) in a line identifier database, and the system may delete the MSISDN/IMSI from a user account database. The system may receive a Telephone Account Procedure (TAP) Call Detail Record (CDR) associated with the MSISDN/IMSI after receiving the cancellation request. Accordingly, the system may use the line identifier stored in the line identifier database to generate a billing report corresponding to the TAP CDR.