Total disregard for my billing dispute

I have a data contract ***) for use with my iPad. Whilst I was away in Namibia from June-Sept 2014, my 3 yr old daughter used my iPad. The data she used exceeded the 2Gb monthly bundle & I received accounts in Sept & Oct for R1250 & R1294. Although unhappy, I understood I was liable. To avoid this happening again, I visited the Tygervalley branch & requested the data be capped which the agent did (see your records). I again traveled to Namibia in 2015. I was not afraid of the possible data costs as I had a cap in place. However, on my return, I received accounts with charges for data for July, Aug & Sept totaling R6544. I visited the Tygervalley branch several times in Aug & Sept demanding my money back but was told I needed to speak to a credit controller who would call me. No one ever has. I wrote to the Autopage service desk this week who placed a cap on my data but did not reply to my demand to be reimbursed. I wrote again asking for an opportunity to speak with a services manager only to receive a reply that \reference no. 910191 has now been closed". How can I be liable for out-of-bundle costs if Autopage capped my data account in 2014 ? I demand R6544 reimbur*****t"""