Did you contact reception or management on arrival and raise the issues of the waste disposal, bins and Main road. Did you demand to be moved to a mobile home similar to the one depicted in the photos. Did you demand a reduction in price based on the issues you've raised. If not you owe the full payment.
You accepted and used the accomodation and I assume the facilities of the campsite, it's the same scenario as going in to a restaurant ordering and eating a fillet steak then saying I'm not paying because I didn't like it. If you don't like you leave. If you stay you pay.