Harassment by Truworths

I'm being harassed by Truworths, I was supposed to pay R2400 but due to financial constraints I only managed to pay R1500 and I phoned Truworths customer care ( ********** 300) on the 10th September 2018 , I told them my situation and I asked that since I bought the clothing with a 6 months plan can they please migrate it to 12 months plan. I was told that they can only migrate the purchases for the last two months, I was then told that they will migrate the purchases from the 6th July to the current month and I will get a confirmation SMS. I waited and didn't get the SMS instead I got an SMS that say that I must pay R3340 immediately , I then phoned truworths again on the 12th September 2018 asking why im receiving this messages whilst I've requested for my account to be reviewed, the lady told me that a journal has been done on my account they are just waiting for the manager to approve and I will get a response in three working days and I must ignore the SMS. My problem now is that im getting calls from truworths the no is + ********** 2961 telling me that I have to pay R3340 immediately and when I ask them about the arrangement I've requested they tell me that they don't know anything about that and it doesn't show that there are any arrangements done in my account. My phone no is ********** 172 and my I'd no is ********** 310086. This is frustrating me because as a customer I'm supposed to be accommodated when I request for this when I have financial difficulties, I'm not shying away from my responsibilities and I'm willing to pay but I don't like the way I'm treated by truworths.