Why does my trade execution price not match what I’m seeing on the chart?

The times on your FXCM statement are in UTC. You can change the time zone on your charts to UTC by clicking on System, Options, and General Trading. Edit the “Time Zone” drop down to “UTC” and click on Apply. Marketscope charts default to show the “bid” which is the sell price. To see the buy price you can click on the “Ask” icon in the chart toolbar. Note that if you are closing a sell position you will need to reference the ask price. 
On some instruments, there may be varying levels of liquidity available and the prices on the charts display the bid and offer prices that FXCM creates. In the event that liquidity at the best price available is exhausted, an order will be filled at the next best available price which may not display on the charts. The chart price will update when the next new price is received. This is relatively rare and is more likely to occur during illiquid market conditions like news announcements and when trading exotic currency pairs.