BAD SERVICE!!!!!!!!

Car service city at Protea Glen Ext 16 (Glenridge) gave me very poor service yesterday (02-08-2018). I called two days before and spoke to a lady by the name of Nomshado. I requested a quote on getting new rear drums and rear linings, I gave her my full car spec including the year model and she sent me a quotation amounting to R2147.46. I accepted the quote and asked to book my car in for the Thursday and she said it was fine, I asked how early I could drop it off she said 7 am. When i got there at 7 am they were just opening (i let it slide) but there was no one really to help me, except for Danny who looked confused as f**k when I told him what I was doing there. I told him I was there to get my drums and linings replaced and he said its fine you can give me the key. No documents were given to me to confirm that I had dropped off my car even after i had inquired about them. I gave him my key and said to him "do not do anything else to my car before letting me know". I asked to be dropped off but there were no cars available and no alternatives were made to accommodate me. I went home and I received no communication from them throughout the whole day. At 4 pm i called them to find out what was happening because i knew they were closing soon and Nomshado only then told me how they were struggling to get rear drums but they finally found them and the guys are busy installing them. I asked how long it would take and she said 30-45min. I then requested her to call me once they were done. 5pm came and went without receiving any phone call then i called them back to find out what the status was on my car, she then gave me a whole story of how the guys got caught up with something else and suggested that I come fetch my car the next day and i refused then went to their workshop. When i get there, Nomshado is not there and i was now dealing with Sam. When i ask him what is happening with my car, he says, with confidence "we have skimmed your drums and linings and here is the invoice" i'm like hang on, who gave you the authority to do that? He then gives me a whole story of how the drums that were delivered were actually for an older modern and that for my model they came to be more expensive than the quote so they then decided to skim them because it would be cheaper and besides the drums are as good as new. Bear in mind that not even a single person bothered to call me throughout the day and instead I am the one who was a nuisance calling them. Now I am faced with a R3617.46 quote because they f***ked up with pricing. I am so angry and feel like i am being ****** because of *********** and unprofessional individuals who do not value their customers. Everytime I ask them what the solution is to this problem all i get is I DONT KNOW. I mean how can you not know.... guys please advise, I do not want to pay this additional amount but I need to find out how i can go about this.