Flashing volume light on my nait 5i HELP

As per title,

Happened around ten minutes after playing some music, everything was fine, i took out a cd, placed in another, sat back down & nothing, flashing volume no sound!

Everything is connected correctly using the phono inputs with Chord cable, same with speaker cable, why would it be working fine then stop like this, i had the volume set to 9 o clock, a very moderate level.

Very concerned as i have just splashed out £400 for this second hand, guy dropped it off in person & worked perfectly alongside the CD5i until this. Had around 2 hours of use since purchasing 2 days ago.

Any help would be appreciated

Contacted Naim but will need to wait until Monday for an answer.