4 days and the phone is still not active

I received a call from what I was lead to believe was a Telkom representative. They asked me whether I wanted to upgrade my phone via my contract with Telkom Mobile. I informed them that I would, and they then discussed which phone I would like, etcetera. I received the phone within the allotted 4 to 7 working days (which was on Monday this week). Since then the phone has not been activated. I have attempted to get in touch with them on a number of occasions, but nobody picks up their call. Telkom mobile has said that they are the only people who can activate my SIM.