No Communication to customers

I purchased a car from q-cars in May 2017. The sales guy by the name of Taps did not inform me that i had to do the license disc again within 60 days of the roadworthy test. As the old license disc was about to expire in 31/01/2018, i went to the traffic department in December to renew it, only to find the traffic department telling me that i have to do a roadworthy test and it must be traffic licensed before i can get a new license disc. I called q- cars and Nicolene told me they will not be paying for the roadworthy test as it has been done before and Taps said as it is his fault of not telling me to do a license disc , they will pay for the roadworthy test. so i paid and went back to the traffic department which they charged me R840 for the traffic licensing which i feel it should not be on me because of their no communication to customers. if i had been told these things before the roadworthy test expired, i would have obviously renewed the license disc and i would not have paid so much money for a sales person who does not tell a customer these things and keeps on telling me that " they will pay for the roadworthy test again because they did not tell me" and now he is saying the same thing " that they will refund the charges for the traffic licensing" . and whenever i talk to them, Nicolene tells me that my 6 months is over. All i want is my refund that i keep getting promises that i will be refunded which i do want paid back. Please help.