Overcharged

Initially I requested an upgrade to Iphone 6 (black handset). Handset was delivered to me,but in gold color. As this was incorrect, the handset was returned and upgrade was cancelled. In June, I again upgraded and this time choose Samsung S6 handset. I was then charged incorrectly for 2 handsets and it appears that I am still on incorrect Iphone 120S contract. I would appreciate it this could be sorted out as soon as possible and that I get refunded for the incorrect charges on my account. Thank you