Greetings ID community;

I could really do with some help, as this is the first time that I have been with ID and not wanted to stay. I am within my 14 cooling off period, but I have unfortunately activated my SIM (only to send and receive a text to check that everything is working). However, I am not a fan of my new handset and I would like to return my phone. Upon requesting information about leaving I have been informed that leaving within this 14 day cooling off period will result in me having to pay the £647.00 for the device. I'd like to know if that is correct because I'm having a hard time understanding what I am being charged for, when I am within the timeframe of being able to return the handset without penalty? 

Any help/advice would be greatly appreciated 🙏🏽 my thanks in advance 😇