Bought a Vehicle and its Faulty and they not willing to cancel the buy

the long and short is I bought a car on 31 Aug 2017 which has been back and forth to the dealer ship (CMH Nissan Midrand) and Car Service City for Repairs going to as much as R10 000+, I have been without any means of transport these times the car was in. wesbank got involved and still is useless, I payed +-R**** for the car and they not willing to assist to cancel the buy. yesterday the car broke down with me again next to the road for the 2nd time 12 days later after the last time it did. last time it broke it went in at 2 Jan 2018 I only got it back on 01 Feb 2018. the dealership wont help or reply on any of my emails nor does the person from the bank now. I have asked to cancel the deal I am about to loose my work over this and no ones cares and wants to help.