I bought a new Nissan X-Trail last month. After a week there was a system fault and the car would not switch off. I took the car back and the dealer said they fixed the fault.

Six days later, the fault returned. I returned the car to the garage and said it wasn't fit for purpose and required a replacement or a full refund. The dealer said I needed to contact Nissan customer service. I did this and feel that they are dragging there feet and there is not going to be a good outcome.

I have been advised that I should notify them that I do not authorise any further repairs. Nissan customer services rang and asked how I felt about them soak testing the car for a few hundred miles to check whether they have cured the problem after changing the Ecu. Could you advise on how to proceed?