bad service

Took my daughters phone in last Sunday 26/10/2015, bought her phone December 2014, Battery pop out. they told me they will give me feed back on the next Monday 27/10/2015 never came back to me. After numerous calls they phone me back on Thursday to tell me MTN will only collect the phone by Wednesday or Thursday. I've ask them for a loan phone they told me they will let me know but there was no response. Me and my daughter went in on Friday afternoon through a tantrum about the bad service. They phone me back 11h30 told met that the phone will be picked up today or tomorrow and I will be waiting for about two weeks. My daughter will be with out her phone for about a month. I am honestly disappointed with their service, I don't see the point of them offering me a warranty if I cant make use of it when I need help. I want this issue to be resolved ASAP coz we cant go on like this