client manupulation

Please Mtn people I'm tired of being ********** the few cents I'm hardly working for. <br> I changed my contract from a R200.00 package to a R100.00 airtime package ?but my bill came more than usual. Went to enquire from the store and was told the migration is charged and I understood.<br> Paid the extra charged amount in full, but instead of my instalment going down since I was getting less airtime it went up again to 220.50 which I don't understand why because I'm not using an open line. 12 June 2015 I paid that amount in full now on the 18th of June I'm send another statement with 230.50 from where?<br> Please I need explanation because I'm not a money tree you can just take money from like leaves shame.