Migration Charge and Incorrect Pro Rata Bill

I migrated in January 2015 to a bigger package from 7.5GB to 15GB LTE data contract. What has happened since is that i have been charged a migration fee every single month when on the invoice it says One Time Fees. Insult to injury is that I migrated upwards therefore i should not even have been charged a migration fee. So that alone is R170 x 11 months = R1,870.00 credit which is due to me. Secondly in the month that they pro-rated the 2 contracts (January 2015 invoice) something very funny happened being that the total contract value is R627.50 (New more expensive contract) but in their calculation i get billed for R1,031.53. I am no genius but common sense would dictate that the amount cannot exceed R627.50 as I did not utilise any excess data. Account number is ***.