Being Overcharged / Faulty \Pre Owned"device"""

Contract was due for upgrade. Called Vodacom in Jan, the consultant denied my request for the s4mini on uchoose at R199pm & other devices I asked for, I was told I don't qualify, she persuaded me to take the iphone 4 which I queried about. She stated my monthly subscription to be R149 pm as advertised. I accepted that deal. However my Bank reflects R219 taken out monthly by vodacom? When my bill should be R149pm? Approx R160 with CLI. I called Customer care last month, no proper explanation other than being told my bill is R219pm? It doesn't make sense as I was denied a contract of R199 for the S4mini, yet I qualified for an iphone at R219? Not only am I being overcharged but to top it off, I am given a \PRE OWNED"device which the consultant failed to mention to me! The words \""PRE OWNED\"" was covered up by a vodacom 1 year warranty label. I didn't want to make an issue but the device lives up to its standards as it has been faulty since I got it. Had I known I would be getting a second hand refurb unit"