Bad service

I am struggling to get a refund from MTN insurance which is now administered by Pinnacle.I am with this insurance for more than 10 years and has at all times been a loyal client paying all my premiums without fail.I recently discovered that I have been paying 3 premiums different premiums for a couple of years for 1 handset and same phone number.When I called pinnacle call centre on the 14 November 2017 and spoke to Sifiso Mkhoto he confirm the above and told that was the information they received from MTN when they took over administration.I called again on the 21 November2017 spoke to Valencia Steph**** who also told me there same and referred me to manager Marcha Prinsloo who told me that she will refer the matter to MTN. During this period no one comes back to unless I follow up and all I get is that they will follow you with MTN.I then escelated the matter to Pinnacle CEO Candice Spidalieri on the 15January 2018 who has not even bothered to respond or let alone read my email..I am now frustrated with this service and need someone who can take this matter seriously..