Indoor Kentia Palm drooping and bending stems

My indoor Kentia Palm bought from IKEA a while ago has started to droop. many stems bending over and had to be cut away. Was it over watered or under watered? Some leaves did shrivel but I think it was after the stem bent double. Some stems seemed rotten when I pulled them out. I've tied the stems together with a  tie to prevent any more drooping, but I am no clearer on the problem and a recovery solution. I'm told it is a slow growing plant so new fronds may take years to appear.:-(

Ideas welcome.