Wow! I’ve used this product since it began and have not heard of this happening. There is a mains switch on the back of the unit and a standby switch on the front. Try turning off the mains power for a few seconds and while depressing the standby switch on the front turn the mains back on. Keep the standby switch depressed for 10-15 seconds or until you hear the cd feed initialize. If the disc hasn’t come out try the eject button again.
If all else fails your best bet is to email support at Naim directly or search the articles/posts on their forums. good Luck!