Overcharged on bill

I ordered a wifi modem with 2 GB of data per month for R149.00 online. It got delivered and everything was jolly. It was understood that once I reach my quota, I have to recharge. I even downloaded the Vodafone Mobile Wi-fi app to track my data usage. 1st debit order went off without a hitch.<br> On 02 March, my acc got debited with R770 something. I contacted the call centre to find out where this outrageous amount came from. <br> 1. Getting through to a consultant took more than 20 minutes.<br> 2. The lady that assisted me was not helpful. She sent me the wrong itemised bill (which I got charged R20 for and I was not informed of this beforehand). She then sent me the correct one. I was then told my contract is an open line which shocked me because I remember specifically asking the consultant that assisted with my contract if I would need to top up once the data is finished and he said yes. This same lady said she cannot change it from an open line to top up.<br> 3. I then called Cancellations and Lindiwe (bless her heart) was able to change my contract to top up. She advised me to log a query, which I did. I got a reference number and 2 days later, no call back.<br> <br> I want this resolved SOON.!!!!!