WHAT A *******!!!

A few days ago my mac book air started having problems. I've only had it for 3-4 years. I was unable to connect to wifi or bluetooth as it was blocked and I was unable to change the settings. On the weekend I took my macbook to the istore which I wouldnt normally do because I know how expensive it can be to repair.. I was right. In order for me to just give my computer in to be 'assessed' I had to pay R600 upfront, and I was like okay that's not too bad. As soon as I letf the store I got an email to tell me that I could collect my device? Am I missing something? its only been 2 minutes... I just left it until the following monday. I gave the store a call to see what the update was. They told me there was an error and they cant pick up the R600 fee that I had paid for the 'assessment" .... I GAVE THEM THE RECIEPT IN THE STORE?!?! Anyways they apologized for the mistake and the next email I recieved was on Wednesday the 10th of Feb with the quote to replace my macbook air. R18 000!!!! They told me it was water damage and that it was uneconomical. So they want to charge me for a new computer basically. The computer I have cost R15 000 in store. Please tell me how that makes sense? The newer/latest version of the macbook air that I have Cost just over R18 000 but they want to charge me R18 000 for the exact same computer thats not even worth the price???? WHAT A *******!!! Included in the price I had to pay a R521 Labour fee. Sorry but what was the R600 that I Paid for in the begining? Because it was certainly not worth the price for your IT guy in the store to "asses" it. It was pathetic!!! Anyways there was no way that I was going to pay that amount as I cant afford it and I sent the rejected signed quote on the same day that I recieved it. 5 days have passed and I havent recieved any communication whatsoever and on monday morning I get an email to tell me to either accept or reject the quote that they sent me. Since I had already sent it in 5 DAYS AGO I decieded to give them a call as to when I should expect to come and collect my device from the store. They left me on hold for 11 minutes to find my reference number which i had given them just to tell me that the service center hasnt recieved my rejected quote. And that I should send it again to the correct email address that I had already sent it to to which I had also asked a follow up question and they responded to that but didnt capture the quote I attached? The lady that spoke to me on the phone at the istore didnt have a care about my issue as she didnt know what to say to me nor what to do. I am completey upset with the poor service that I recieved from the Istore in Fourways Mall. I had higher expectations for the Istore... Surely the staff has been trained on what to do since the store always seems to be busy. Very dissapointing