Cell phone troubles

I have recently upgraded both my cellphone contracts with cell c, the first in Feb 2015, and the second a little later (if I recall correctly) however irrespective of the date of upgrading, the second phone's charger out of the box would not charge the phone - luckily we ordered the same phone, so had a spare charger.<br> <br> The first phone, I now have battery problems with, the phone does not even hold a charge for 4 hours, after charging fully.<br> <br> This is unacceptable.<br> <br> I insist that Cell C give me a new phone, as this is unacceptable, I have been a customer of Cell C for close on 5 years, and never had this kind of problem.