No refund from Wonga

I took a loan at wonga in 2015 and i joined debt review in 2016 and i have been paying them since then until in the middle of 2017. Wonga sent an email to my debt revie (Debt Busters) on 25 June 2018 with a letter my wonga account was written off in February 2016 of which i have to get a refund. I sent my ID and bank proof after then. No payment was recieved from wonga. I tried to call wonga but they told me that they can only talk to my debt review. I then contacted Debt Busters for assistance in 16 July 2017. Denver Magano assisted me and he sent an email to wonga asking if there is a refund for me on 1 August 2018. He sent an email bank advising me that wonga responded that there is a credit balance. I sent to him my bank detail and ID again and he told me that the money will reflect into my account within 3-5 working days. Today the date is 15 August and i still did not get that money. I expect not less R3000 in calculating all the money i have paid through my debt review.