Would never buy a car from the Carshop

I found a car a liked and was priced well under what the car was worth. I questioned this 3 times only to be told that the low price was set buy the company that wanted to sell the car on. I accepted this and they were very helpful up until the day that i went to test drive the car. there were a few points i'd like to make regarding that.

1) I was told the car hadn't been cleaned in time for me to test drive which was fine i could cope with that but then found out they had done absolutely no checks on the car to see if it was even road worthy. Very concerning as we had just taken the car for a test drive on a busy dual carriage way
2)We were concerned that the head gasket may of been leaking only to be told by the salesman that he didn't know anything about cars so wouldn't know. Not very reassuring from someone that is selling you a car.
3) the icing on the cake was when we sat down to discuss whether we wanted the car we were told there had been a mistake and that the car had been priced incorrectly and was in fact £3k more.

It has been nearly 2 weeks since this experience and i am still waiting for my £99 REFUNDABLE DEPOSIT to be put back into my account.
The whole experience was completely unprofessional and would rather ride my bike to work then ever buy a car from them