refusing to fix a software issue on the phone.

i booked in my phone at vodacom on the 5th of January 2016. and i was told i should expect to get my phone back within 7/10 days. however on the 12th of Jan i received a call from one of the tech guys from vodacom to confirm the billing to repair the phone. they wanted to charge me R 6800 to fix a cracked camera glass which i turned down as i felt it was too much besides the phone was still under warranty or is still under warranty. this is worrying me as i have saved all my data and apps that i use on a daily bases on that phone and now they refusing to fix it because i dont want to accept the invoice for the cracked camera glass. vodacom is ripping us off on a daily bases with high tariff bands and airtime that just disappears and they cant explain why and how.