OBJ files will not have the correct materials applied and in most cases missing textures as the format doesnt handle even standard material conversion very well.
FBX is much better for transfering assets between 3d software however it is up to the artist to set up the materials and export settings so that its compatible for the software its going to specifically. Without the scene being set up for blender (which I use with my models - much easier with PBR) then there is almost now way its going to look correct without adjusting every material.
In this case it looks like its setup for 3dsmax, additional formats will most likely require the buyer to set up the materials/lights/render settings themselves. You should contact the buyer and ask them for a file conversion if possible.