Invoicing; invoicing services; business invoicing services; accounts receivable billing services; accounting services; administration, billing and reconciliation of accounts on behalf of others; operation of telephone call centers for others; management of telephone call centers for others; telephone answering service; information and data compiling and analyzing relating to business management; analyzing and compiling business data; analyzing and compiling business data for business purposes; marketing services; marketing consulting; advertising, marketing and promotion services; development of marketing strategies and concepts