Contract ended before the 24 months.

I called telkom mobile call center to find out when my line is due for an upgrade and the agent told me to go to my nearest store and do a swim swop, when I went to the telkom store I was then told I need to log a call to have my line activated because it was suspended, Nobody called me to inform me of this. Now I am being told that my contract with Telkom has ended before the 24th month. I would like Telkom to refund me my R600 which is in credit on my contract ASAP.