Day light *******

I have been with vodacom for years, after multiple contracts that I took, I started paying unstable amounts, every time I call in, am told I took an advance, the funny part, is the 1st time I called, I was given that story, but later on refunded, then after some months it started again, and also subsequently am told I took an airtime advance, the Sim card in question is never out connected to a phone, its forever on a wifi router, the amounts fluctuate, for eg R18 advance am charged R16, 52, when I look at the given amount of the supposed advance, the charge does not correlate with the advanced amount. Am done with vodacom, as my contracts are due, slowly I will await the date of end.