Incorrect quotes & charing additional costs without checking with the client first

On the 9th of July I brought my Kia Picanto in for a new tyre and wheel alignment. I was informed that I would need a new tyre rod and shock as there was damage to those parts. It was then discussed with the gentleman that I would bring the car back in after payday as I did not have the money for the parts at the time and they would re-do the wheel alignment for me free of charge as it fell within a month's time. One month later (5th of August), I bring my car back in and pay for the parts and service for them to start work on the car only to find out they do not have the correct parts once the car was already being worked on. Got called again on the 8th of August and brought the car back, only to receive a call AFTER they installed the new parts telling me that it will now be an additional R1125. I am floored that this was not quoted on correctly when payment was made and for Dunlop to just go ahead and install parts at a higher cost without checking with me first. Shocking service.