Cellphone Collection Request - 3 weeks and still no service!

I upgraded my cellphone over the phone (online) and received the device the very next day - this was 3 weeks ago. The day the phone arrived it overheated and I explained this to the Cell-C representative when he called to ask about the phone. I then called the follow up and collections department, the retentions department (084 145) and the customer care department to request them to come collect the device and reverse the upgrade. Three weeks later and still nobody has contacted me to arrange to come fetch the phone nor reverse my upgrade.

On two separate occasions I tried to return the phone myself to my nearest Cell-C store and on both instances I was told to call 084 145 without any assistance, I explained to the 084 145 people that I've called them for 3 weeks now and still nobody has come to pick-up the phone.

All I need is an address for Cell-C's Head Office and I will return the phone there today myself, as I cannot wait another 3 weeks hoping that by some miracle somebody will call me to come collect this phone and reverse my upgrade.