Delivery charges

I purchased a washing machine Defy DTL149 13kg met top load on credit on the 11/06/2018. On the Tax Invoice (090538) they added delivery charges of R500.00. I have a document stamped and signed by the security that I collected the washing machine. I phoned them numerous times and have gone to see them concerning the delivery charges. Today the 13/08/2019 I was informed that it is there company policy to add the delivery charges so they can see where I live. I am very unhappy that I have to pay R500 for delivery charges. According to the financing department there is no way they can rectify it.