Avis (a very irritating situation)

I rented a Ford Figo from Vryburg to Bloemfontein for one day. I was told the car is 840. And 1000 for one way fee. The sales person told me it comes with more than 200km free and additional kilometres will be billed at R1 something. I gave the car back refuelled and in mint condition. I was only refunded less than 500. And charged over R3500. This is impossible according to me. Additionally to that. The sales person told me the car needs to be returned in Welkom but they will be closed on the day of return and that they open at 4pm until 5pm. I sat there missing my transportation untill 4pm.which made me loose money because my transportation was non refundable. I please want this corrected ASAP and no excuses will be accepted. I will not be billed anything other than what we agreed on. This is ridiculous. Horrible service and communication, I would not recommend them at all and by the look of complaints they seem to be a terrible company and something needs to be done.