Unhappy about Service/after service from Webuycars

I would like to complain about my Experience at We buy Cars. We started off at Midstream Branch and only found problem cars on the floor/in the warehouse. Then we got to Silverlakes Branch and there I bought a Kia Sorento 2006 model 3.5 V6, and this was just two weeks ago..... what a mistake! I bought the Car by Jens du Bruyn after we took it for a test drive in a business complex where you cant really drive the car faster than 70kmp/h because of the speed humps and the amount of feul they put in for test drives is also a joke. Ok so they had to jump start the car from the beginning as well and with that there was a sound almost like it back fired. So we checked everything and it looked good and also JJ a Mechanic there and also the son of Jens du Bruyn said the car is in good condition and is definitely a good buy. So we bought the car and left. We then stopped to put feul in, I let them fill up the car R1200 later to only get the petrol station attend to tell me theres a lot of feul leaking from my car at the bottom, so I lost about R300 of feul there. We then phoned Jens and informed him, his answer was "it might only be a breather pipe thats faulty". I had the car by Kia Rustenburg and there I was told that theres a after market computer in already. We then informed Jens du Bruyn already. I drove the car for a week and then started getting problems, and the last week up untill today which will be the second week of purchase the car is standing because according to diagnostic test its computer box failure. So Francois Venter from We Buy Cars only advise us to try and sell it back to them online. But we buy cars send one of their sales guys to come and have a look at the car only to tell me no they dont buy "non runners". Wow and then Francois Venter tells me to take the case to "the Ombitsman". Between the Dealerships, the buyers and the sellers of we buy cars theres a big communication gap. The buyer came to us with no info from the office/sales manager that its a "non runner" because the car does not even start! No explanation was given to the buyer that came out to us