Vodacom ripping people off

I have been a Vodacom client for a long time and I am disgruntled by the way it’s treating its clienteles lately. My phone had a splintered back glass and when I calls someone they can not hear me and went to your store to fix it under my warranty but I was told to fix back glass first then the phone will back on warranty. The first consultant said the mouthpiece is clogged. I did as I was told forestalling that my problem(the phone will go under warrant) will be solved but to my surprise I was quoted 1886,18 for job number ********** 3 fixing the mouthpiece which is unclogging it as said by your consultant. I called back the store for clarity only to realise that the agreement I was no longer standing. I feel betrayed by my service provider. Why do you have to lie to customers? I feel ****** and taken advantage of. Please assist me before I escalate this issue.