Unfair charges

I have been emailing cellc multiple times. They would call me 2 to 3 times a day of which i would only speak to them once due to the other times they would end the call as soon as i answer. I lost my job 3 years ago so my fiance is paying the account via EFT but they charged me penalty fees due to the debt date. So i called a hunderd times to fix the problem and eventually someone help told me that they can't cancel the debt order but i can change the date and i did. Since then the penalty fee was gone. Until last year June it reappeared they started charging me the penalty fee again. My phone is turn off due to this. I have spoken and emailed them about my problem but still they tell me that they would send me a email address or they will send the info to another department and yet the same department calls me back everyday and nothing has been resolved im so tired of speaking to the same people who has no clue as to what they are doing. I feel this mistake was made by cellc and that it is unfair of them to expect me to pay that amount..