Concern over Legitimacy of this call center.

I recently was contacted by this number *** and they said i was due to upgrade my cellular contract and that they would do this for me on behalf of telkom. I spoke to the lady on 4 occasions and she appeared legit and had all of my details. She offered me options to upgrade to and i accepted the deal. She then said that the delivery of the phone would be on the 22 June 2015. There has been No Delivery and when i call the number, i am told that it doesn't exist. Please advise if this was legit or not...i am terribly concerned.