The chairs filled with a good quality material are cozy and give you the best comfort. You can relax as much as you want but as time passes the filling comes out and you cannot use it any longer. The filling can be of any type but should be good quality. If the filling has come out then find ways by which you can get a new one filled in to it. It can be repaired only through this option as no other choice will work.
Cut the cover of the chair and take out the material filled inside it. You will get the liquid which has to be mixed with the filler and then only you can fill in the grooves and gaps which you come across. For more information regarding fillers and colour you can read the instructions given by the manufacture so that one can get the correct idea as what should be done.