Poor Customer Management@ FurnMart

We took a washing machine from Lephalale branch, and paid deposit as agreed. However I missed the first installment and arranged to pay later, and when I made contacts with the store on the 17th, the store says I should pay double the instalment, the other instalment I must pay in advance since I did not pay on time in the previous month. How, I explained that I only want to pay the previous instalment and by month end I will come to pay the current instalment, they refused and threatened to come take the machine. This store lacks professionalism, probably from the Branch to their HQ, because I call their head office, and one lady who said she was assisting she said to me, there is nothing they can do, I must go pay that double instalments. She told me how my education should work for me and Lephalale Store manager one day called me and told me she will come fetch me from work. I do not believe they NCR registered based on their staff conducts.