****ty service by vodacom

I have been trying to return a device for 3 weeks after they promised initially that it would take 7-14 working days. Fine but 14 days later it's still in my possession, another request was made they promised to escalate the matter and ensure i even have a tracking number with the courier within 24 hours, again 3 later still no tracking number or any other form of communication from Vodacom. Here I am stuck with a device that should have been collected days ago. They have made promises upon promises with zero delivery, I just want them to collect the device and correct my bill. How difficult can that be?