LACK OF CONTRACTUAL SERVICE

I have a device on contract with Vodacom ots a little over a year now the battery started swelling so I sent it in for repairs approximately 2 months ago I was told I need to pay for the battery as it out of warranty to which I agreed however they then requested I pay for a cover as well and I disagreed saying that it is not out of warranty my phone has been sent back and forth between clear water store and fourways repair center for 2 months now when I went to fetch the phone it was further damaged with a chip in the cover -I don't understand the back and forth because I am willing to pay for the battery so now I am sitting without a phone for 2months and vodacom cannot seem to care or sort it out....so why Anni paying a contract??????? I am at wits end and disgusted by this honestly....vodacom has inconvenienced me for over 2months now and the fight is draining me honestly we pay on time and get this ****ty service it's not fair at all!