FZ82 something inside lens

I have a refurbished (by Panasonic) FZ82. A small black mark appears on all photos and videos and can be soon through the viewfinder. I have had a lens filter on all the time but it is not on that. I have cleaned the lens thoroughly but it remains so somehow it is inside. Does it have to go back to Panasonic for repair and it is 13 months old ?