Under quoted, twice, couldnt care less!!

A few days ago I broke my Sony Z3 screen, So it needed to be repaired. I went to autopage hillcrest on Sunday to get a quote and the lady behind the counter tells me +- R1000. Great. I come back on Monday and I tell the same lady I want to Know exactly how much it would cost to fix. So she picks up the phone to call someone for a price, and I hear her give all the correct details over the phone. She then tells me it will cost R1800.. (Big change) So with big reluctance I hand the phone to them. Before I left I made it very clear that The phone is my business phone and needs to come back fast. Latest Friday I am told. The next Saturday I call to find out what has happened. They are apparently still waiting for a quote??? That's been done I tell them!! Monday comes round still noting so at 5pm I call again, same story... Anyway. Wednesday, they call me. They have the phone BUT, they know they quoted me R1800 but it is going to cost R2500 now. And my only 2 options are PAY the full amount or they will send it back, remove their screen but will also completely break my phone in the process! Their response to me, Not our problem The supplier quoted for the wrong phone.