Cellc failed to pay my refund

I made a duplicate payment via EFT to Cellc last month on the 25th of April 2023 and contact cellc on the same day to ask for a refund and they told me I will get back my money within 7 working days, however up until today which is the 25th of May 2023 I have not received my money back. They kept on logging over 7 tickets for me, every time i received an SMS to follow up on my ticket, I called and they told me that my ticket has been closed and opened another one claiming that I did not send through the proof of payment which I had been sending to them. I also called in several times to speak to management and I kept being told that management is either in a meeting, busy or will get back to me which they never did. Cellc is still owing me R783. I am so ****ed ryt now cause I am not being assist accordingly.