Account billing for Pensioners

Mr S B Kgang is a pensioner and trying his best to pay Eskom every month, Account no : *** on the Billing date - 2014/12/16 Total due was R1700.73 and he paid R1700 at Shoprite. Billing date 2015/0112 Total amount due was R622.65 and he paid at Shoprite R622.65. Billing date 2015/02/16 Total amount due was 0.00 and he was advised by the customer agent to pay atleast R200.00 even though the Statement indicates a ZERO balance. Billing date 2015/03/16 Total amount due is R0.00 again... now My father inlaw went to Eskom on the 17/04/2015 to pay for the Prepaid installation and now he was told that he needs COC first and and now they printed a new statement with a Total due that needs to be paid is R1 996.95 before they can chage his box to a prepaid because he can't afford to be paying all these rediculous monies, He is a pensioner . Please try to fix these billings for him so he can at least have a prepaid account.