incorrect data billing ...daytime *******

i am using telkom mobile Internet which i receive 10 gigs day use and 10 gigs for midnight till about six.From June 2015 i noticed my data being depleted before the month ends.I purchased more data to use till end of month.This went on also during July and August. At the end of August i decided to investigate this matter as i know i could not have been using all this data.I called the customer care centre and spoke to Gishwill Koen ,Mandisa Cele, Queen Mhlongo on three different occasions and they logged calls for me even sent me detailed billing verifying that when i used data after 12 am the data charge was being deducted out of my 10 gigs for daytime use.I phoned every other day and was informed that their technical department is looking into it.I have been waiting now almost a month and half sort this out, i pay my bill via debit order and purchased more data from them and i feel as if i have been cheated and ****** as nobody there cares to sort out this matter. Today i spoke to a team leader Miss Pule and was told i would be called in 10 minutes,no one called. There are Telkom staff at the call centre who even say that there is alot other customers complaining of this also.