Absolute bad service from Cell C

For the past 10 years I have been a loyal customer of Cell C. I have been paying my account up to date each month on time... no hassles! That was until I checked my statements carefully. There was some overcharges on my accounts! Remember now, these overcharges has already been paid by me in full.... I wrote an email to all the Cell C big bosses and even the CEO's office, but to no avail! But when you don't pay your account in full then Cell C cuts your services! And on top of that I signed up for C-Fibre in April for R 907 per month. However, for the past 3 months they have been charging me R999.01 per month(which I already paid!). Now, when I want an credit there is all sorts of long stories they have. This is absolute bad service from Cell C and even their big bosses.