phoney phone warrenty

I have been a Vodacom customer for approximately 10 years. My phone is my link to my students so I am never without it and pride myself in keeping it scratch free and always looking new. Never have I returned a phoned on any of my contracts until last week Friday. The phone is a year and half old and the battery expanded while charging. The staff at Vodacom Shelly Centre were extremely unhelpful. The 3rd person I spoke to was the only helpful one. She explain as I am still using the original charger that came with the phone it falls under warranty. I had to make R1800 debt to get a new phone and a sim swap as Vodacom don't give phones to clients to "borrow" while their phone's in for repairs. The 1st two staff members actually made it round like I will ***** it. Now I get an sms, not even a phone call to say I must pay R750 odd to repair the phone.

The battery is part of the warrenty, I use the original charger and my phone still looks new. Why must I pay for a repair when I'm not responsible for the damage?

The service from Vodacom has gone down drastically in the past 2 years while their charges has just gone up