You did the right thing giving your unhappy seller a full refund.

Your description is 'iffy' and not a complete description.

MDF is a man-made 'particle board' product-made from small leftover wooden particles/sawdust and has glues,resins etc added then subjected to much pressure.....it is a processed/manufactured product and I would not call MDF timber or 'wood' per se.

I have worked with both natural timber/wood and MDF. MDF does not have a 'grain' in it like wood/timber does.

Being an avid buyer of fabric I get cheesed when a fabric that is obviously a blend of natural and synthetic is described as 'cotton' which is not totally untrue if it is polyester/cotton blended and not untrue as the seller may not have described as 100% cotton-but item description is not clear in this case. Most fabric sellers, if they don't know the exact content of a fabric usually put in the item description 'not sure of exact content'.

The clearer and more precise you make your descriptions is the way to go, leaving little room for argument, happier buyers and pathway forward to a great transaction.