My parents have an e-commerce website and they're pretty high in Google results. If you Google one of their products, their store is showing up on the first page but links to an old URL
https://www.example.com/truck-wash.html, which is opening up to a 404. The actual store has a URL of
I think this is called indexing (correct me if I'm wrong). My mom has called their web developer but for some reason he won't fix it or can't fix it. So, my question is, how difficult would it be to switch those two links out and what is the process to do so? My mom wants me to call him and it seems like this would be a pretty easy thing to do, but I'd like to know for sure before speaking with him.