Poor service from Vodacom

I cancelled my contract on my ****le as I have installed fibre. The consultant very kindly changed my contract on my mobile to flexi 230 at promotional cost of R179 per month from 1st July. What has transpired is that the ****le has been canceled but I am still being charged the original debit amount and not the R179 p/m. For some reason they have added 20gigs of data to my phone. I have tried to contact Vodacom but after a long wait on their help line I was disconnected. What makes matters worse that cancellations can only be made over the phone