VW Cannot fix a car that became problematic 2 days after collection

On 2nd December. I took delivery of a Polo Vivo FROM Mastercars. 4th December, EPC light and ABS came on. I communicated openly with the sales person involved. Eventually I had to take it in. Upon taking it in they said they could see no problem. I took the car and they told me to continue driving and contact them immediately as the light goes on. This was on the 15th June. I drove 200km testing the car and the light came on at 22:05. I contacted Roadside assistance and got the worst service and they did not dispatch anyone to come look at the car. At this time I had sent videos and one of the technical guys said he could not prove it is my car. So at this time I took a video starting from the number plate all the way to the dash board. Sent it to the Sales Manager too. Brought the car in. And they saw the car had a history of replacement of the accelerator pedal. But apparently VW SA recommended to change this AGAIN! They changed it and I collected it on the 28th/29th December. I drove just above 700 km around the province and now the EPC light is on again and the revs always go up without me placing my foot on the accelerator. I am not getting the right attention especially with the fact that the only time the car worked correctly was the first two days!!! Now I need to raise with my finance house to arrange for cancellation of this whole deal.