Long Over Due Refund from NDS

I have been requesting for my refund from NDS for a month now. Every time I call they tell me it’s with cell c. The staff is also very rude. It’s been a whole month now of going back and forth and still haven’t received my money back. When tables are turned they pester me every day wanting their money. I am EXTREMELY unhappy with the unprofessional service I have received. Can someone from NDS assist me with getting my refund pleaseB