Billed twice

my name is Jermina and i have been ********** by Telkom, I made an upgrade on the 31 July 2017 and i was told that i would be charged a pro rata fee for the 1 day only as the next would be a new month.I than received my statement and i was billed twice meaning i was billed for July and August mind u what happened to the pro rata for just a day. i called in and was told i shouldn't complain as i received a full functional phone with a battrey.. so in the other words i have no authority to complain as the phone works. i cant be charged a full month for a phone i took out on the last day of the month. YES i can be billed full price for August that's understandable but for 1 day and pay full 379 that's outrageous.... please assist as my phone is suspended as we speak and i am a proud customer of Telkom and i have been your customer since 2011 but after this im really dissapointed i have had endless upgrades with you and this has never happened