Istore SA Online Trade-In BAD Service

I did the online trade-in for my Iphone and they came and fetch the phone for evaluation. I was then requested to either confirm or reject the trade-in amount. I did that and since then there has never been communcation. I have called the call centre several times and there is no assistance is to when the refund or voucher that they indicated I will get. I am now regretting to the trade-in because now I am phoneless and its frustrating because I need to buy a new phone. The service I recived from Istore Online is disappointing and I never thought a big brabd like this will have poor service. I just need my refund or if they can't please bring my old phone back.