If your application is refused, you will lose part of your fees if paid but you can always apply under Express Entry again and will have to go from the start.
At this stage, don’t start thinking of the “what if’s”. You are going to be fine. I’m not sure what grounds CIC ask for additional documentation. Take me for example. My ITA submission was rejected on the 16th day of submitting as I forgot to include my common law letter. I would have assumed they would ask for additional docs but this wasn’t the case, it was simply cancelled. I think had to go from the start.
Just remain positive, you’ll find out at some point when you have an update.