Zero spending limit but 3 months HIGH ACCOUNTS!!!!

We are very unhappy customers , I personally came in to Telkom all the way from Uitenhage on how many occasions now - To get our account sorted out I was informed on the 1st of October - TELKOM confirmed this will not happen again and that my son's number *** has been Activated for ZERO limit but this is going on now for another 3 months, I need you to get this sorted out on management level now!!!!Refer to attached last 3 months accounts now.... My son's number was never a problem - only the last 3 months see attached the accounts - we signed a contract agreement for no spending limit only his 1GB per month . I honestly do not know why I get these high accounts this is not acceptable we have not signed up for extra R500 spending limit For 3 months this is now happening R500 x 3 = R1500 how on earth can we afford this for a teenager - I do not even use this type of money for myself I was informed in your store end September this is fixed!!! My son even received sms in your store your spending limit is ZERO!!!My son confirmed on + - the 10th each month his data is finished as well - my husband wants printouts/proof for this where we signed agreement to xtra limit..