Acoustic Solutions DVD80RW300 Sound issue?

My Acoustic Solutions DVD80RW300 no longer records sound. This started 3 days ago. Recordings prior to 3 days have recorded and play sound ok now. Even DVD's now play sound ok.

Pretty certain it's not the TV as when on the AV channel there is sound but it switches off as soon as the Acoustic Solutions DVD80RW300 is turned on.

Have reset to factory settings with no luck. Called the helpline who weren't very helpful.

Any help would be appreciated.