MTN Direct sales extremely poor customer service

I upgraded my cellphone contract via MTN Direct. The device delivered didn’t meet my requirements and I called back to return the device within the 10-day cool down period. None of the Stores in my vicinity was a Direct Store so I can’t return it myself. I have requested assistance from the Direct team, they indicated they will arrange pick up from me via courier. It has since been 5 days where I have been trying to contact the sales person who upgraded my phone, I have called more than 20 times, everytime I get told he will call me back. This is resulting in the 10 day cool down period lapsing and resulting in my contract upgrade not being finalized