Pathetic Service and no Customer feedback from DMC

I had mistakenly paid up an account with DMC, this was for an account which I had already paid 5 years ago, so on the 11 April 2018 I started the process to get my money refunded (ref ********** 2) 1st. - DMC collected money for an account that had already been paid. 2nd I submitted my POP to them on the 11 April 2018 (agent Lunthando). He initially gave me 72 hours turned around time for my query to be resolved. 30 Days later I had to get in touch with DMC to follow up and Luthando had no update. I then gave them more time to resolve my issue and now 44 days later I have not heard back from them. I called the contact centre on the 21 May and requested that my query be escalated to Joan Nel (GM) - who I was not allowed to talk to...she apparently doesn't talk to customers and not surprising I have not heard back from her or the team leader who I spoke to. I am outraged at the lack of customer service and lack of ownership displayed by DMC. To date I have not heard back from anyone as I suppose their jobs are to collect money and not refund monies rightfully owed to customer's which they wrongly collected. DMC your service is pathetic and I am annoyed at your total disregard for your customers. In fact I will be very surprised if I heard back from you on this platform!!!