CELL C TRYING TO ROB ME, CONTRACT PAID UP

some time in may 2017 i called in Cell C customer contact center, asking if i want to to pay off my contract how much should i pay, then consultant asked me if i want to pay it off and migrate it back to pre paid or if i still want to receive my benefits as well, i then asked how much should i pay if i settle and be migrated to pre paid she gave me the figure, she then gave me the figure if i wanted i still want to use the benefits, which i then asked her to send them figure again on the statement, as such i made a payment according what the consultant told me and what the letter or the statement was showing, out of the blue when my contract is left with 3 month, i am debited with for the same contract i paid of when i enquirer with CELL C, they advising that i only paid for 21 months i am still left with 3 months to pay, of which to my knowledge i paid off my contract, so if the consultant gave me wrong amount to pay, how is that my fault and why should i be punished for CELLC faults and now both my line have been blocked because i disputed the Debited which run on my on the 21.01.2018,

can i please have both my lines activated because as far as i am concerned i am not at fault here