Bad Service

I purchased a 2013 Suzuki Alto from McCarthy in Hatfield,Pretoria on 31 January 2015.Mentioned to the dealer that the license disc expired in August 2014,they confirmed that they were aware and would sort it out.Been sending correspondence but to no avail.On 10 April 2015 I was involved in a motor accident and have been unable to do an insurance claim (which I am still paying) as the license disc was expired.In June I was promised that I would get my car back in 2 weeks time,it is now 3 August and nothing.I am still using their loan vehicle and have no idea when I will be receiving my car back.Been paying HP and insurance for four months now for something I do not have and don't know if I still want the car as the service I have been experiencing is totally shocking.