Bad service

I bought in april blankets cash. And after i order pots to the amount of R3500 through an account,the money is payable in 6 months. My first payment was on 2 May to the amount of R1000,and my installment is R600. On the 7th i got a messege saying i am in behind with my payment and i should pay R3050 of which was the balance. I called them and they assured me that they have made a mistake and they are going to fix it. Again i paid R1000 on the 3rd of june again on the 4th i got another messege that i should pay R3154. I called again and they said they will sort it out,to my surprise its been 2 months now since they promised to sort it out and now i dont have a buying power and they they have also added R140 and i dont understand what was for. And now im afraid i might be blacklisted after this. One more thing their agents said they cant get back to me since they are busy with their work. This is very dissappoiting from a company called homechoice with its good history.