Worst Service I have EVER received. ******!

I recently bought a vehicle from WeBuyCars Brackengate branch.

Upon inspection of the vehicle, the Dekra report noted that the vehicle has a navigation system fitted to the vehicle. I took the vehicle for a test drive and noticed that the navigation system is not working. I directly notified the sales person, and he told me that it's not a problem. According to him, I just have to take the vehicle to the dealer, get a quote to activate the nav, and send it back to WeBuyCars to sort out for me. So I bought the vehicle. I then sourced the quote from the dealer, and send it to WeBuyCars. I requested my warranty documents (Which I still have not received to date) and Info on when my Nav can be sorted out. After Weeks of calling back and fourth, the FINALLY responded with a "Sorry, but we can't sort it out for you, because you signed the Offer To Purchase". I also received a letter to take my issue to the Ombutsman if I am not happy with there decision. Very poor service. I will NEVER purchase a vehicle through them again.