Quote half of final account

I took my Blackberry which I've had for 4 years to upgrade the software and replace the battery. I received a call to inform me the cost would be R445 in total to which I agreed. After a couple of days I got another call to tell me my phone was fixed and ready for collection but to my amazement the cost was now R1223. I went to the store and was told my screen needed replacement which they did without my consent and there was no problem with the screen when I handed the phone in. Now the repair cost is triple than what I was quoted and agreed to - my only options now are to either pay what they want or have the \ broken"screen put back which still leaves the phone useless to me. This is completely unacceptable and having been a Vodacom customer for over a decade this leaves me with doubt whether I want to continue being a loyal customer."""