Complaints about National Geographic Magazine

My complaint in against National Geographic Magazine. For a few years I have had subscriptions for 2 of my grandchildren. In September 2018 I renewed the Nation Geographic Little Kids which was done on line from America. I had no response or acknowledgement of the order as I had had in previous years. After 7 weeks I sent an email to them and only then did they reply that they had received my order and the subscription had been extended for a year. In October 2018 I asked my grandson if he wanted me to renew his subscription to National Geographic which is done in South Africa. He rep**** that he had not been receiving the magazine for a year. I sent an email to NGS Customer Service, attaching my proof of payment in June 2017 as well as their email of acknowledgement stating that the subscription would be renewed until August 2018, asking why the magazine had not been delivered for 12 months. To date they have not rep****. I have the impression that my emails are being dealt with by machines. How can I get a refund or an extra year’s renewal for the 2017/2018 subscription to National Geographic that never happened?