Wrong data allocation on my contract

I took out a cellphone contract in 2016 August. Knowing that the contract offered 1gb of data per month. For a while we wondered why the data runs out so quickly, to only find out that we have been given 100mb of data instead. After numerous visits to the Mall of the South Telkom store, I was not getting any assistance in fixing the problem. After a few month of a logged call ( ********** 5) I got someone to replace the 100mb with a 1gb package from December 2017. It's been 16 months of only getting 100mb. Im still waiting for me reimbur*****t for the shortage of data supp****. Nobody getting back to me re that... But If I were to owe money, you would just deduct it from my debit order.

Please fix this for me