Refund request for missing parts or pieces

Hi. I’m relatively new to selling on eBay and today have encountered a customer requesting a refund due to “Missing parts or pieces”. The item in question was a boxed video game. In the description I stated the video game was an ex rental copy and that the box had been cut down to fit a video case and only had front, spine and back. In another part of the description, I stated that it was only “part of the original box”. In their request for a refund the buyer admits they missed these points in the item description but feels that because the accompanying photos didn’t show the missing parts of the box, they are entitled to a refund. In the photos I only took photos of the parts of the box that were intact as I thought this was enough given that id highlighted the fact it wasn’t complete in the item description Am I wrong to feel that the onus is on the buyer to ensure they read the item description fully and not just purchase based on the photos?