Packet Switched Data Calls

I am on a 24 MTH My MTNChoice 100mins contract. Upgraded on the 03/07/2015 and asked for a open line. When my 100 mins are finished I can still call and will be charges extra for that. On the 20/10/2015 my statement for October had a charge on for \Packet Switched Data Calls\" R389.89. On the 16/02/2016 I logged a call ***. Was phoned today and said that I requested a open line and was charged R389.89 because I used all my data. My open line was not for Data. On the same statement I spent R135.96 on Data I bought. When my data is finished I get a message \" You have run out of data. Please recharge to continue browsing. I dial *141*1# and buy data. If I have an open line why does it then tell me to recharge? Sins the Packet Switched Data Calls I can't buy data, message I get is Insufficient airtime to buy this internet bundle, first increase your usage limit, dial*141*1*7852#. Why is it saying \"Packet switched data calls and not exceeded usage by 100MB and then charges accordinly. On knowledge is power checklist Kiresh crossed out Questionnaire. On Questionnaire is a point \" In the event of a open voice / Date line usage etc. The / means you can choose between the 2"