% APNIC found the following authoritative answer from: whois.afrinic.net

% This is the AfriNIC Whois server.
% The AFRINIC whois database is subject to  the following terms of Use. See https://afrinic.net/whois/terms

% Note: this output has been filtered.
%       To receive output for a database update, use the "-B" flag.

% Information related to '41.221.251.48 - 41.221.251.55'

% No abuse contact registered for 41.221.251.48 - 41.221.251.55

inetnum:        41.221.251.48 - 41.221.251.55
netname:        MSTELCOM-IP-MPLS-CUSTOMERS
descr:          MSTELCOM - PETROTEC
country:        AO
admin-c:        MST1-AFRINIC
tech-c:         MST1-AFRINIC
status:         ASSIGNED PA
remarks:        OrgName: MSTELCOM, SARL
remarks:        OrgId: MST1
remarks:        Address: Telecommunications Center (TCC) - Rua Farol das Lagostas 1
remarks:        City: Luanda
remarks:        PostalCode: 3702
remarks:        Country: AO
remarks:        RegDate: 2016-01-04
remarks:        Ref: http://whois.afrinic.net/MST1-AFRINIC
remarks:        OrgAbuseHandle: MST1-AFRINIC
remarks:        OrgAbuseName: MSTELCOM, SARL
remarks:        OrgAbusePhone: +244 226 633 914 - 882 - 088
remarks:        abuse-mailbox: abuse@mstelcom.net
remarks:        OrgAbuseRef: http://whois.afrinic.net/MST1-AFRINIC
remarks:        OrgTechHandle: MST1-AFRINIC
remarks:        OrgTechName: MSTELCOM, SARL
remarks:        OrgTechPhone: +244 226 633 914 - 882 - 088
remarks:        OrgTechEmail: ipadmin@mstelcom.com
remarks:        OrgTechRef: http://whois.afrinic.net/MST1-AFRINIC
mnt-by:         TF-196-29-192-0-196-29-207-255-MNT
source:         AFRINIC # Filtered
parent:         41.221.240.0 - 41.221.255.255

person:         MSTELCOM IP Network
address:        Telecommunications Center (TCC)
                Rua Farol das Lagostas 1
                P.O.Box 3702
                Luanda - Angola
phone:          tel:+244-226-635-006
fax-no:         tel:+244-226-635-088
nic-hdl:        MST1-AFRINIC
mnt-by:         MSTELCOM-MNT
source:         AFRINIC # Filtered