If it is truly plugged up there is nothing Camping world can do to get it working except for replace it. If you bought it new and ALWAYS made sure the refrigerator was level when on and parked then it's likely not plugged. If however you run the refrigerator with the RV significantly off level, then yes it's likely plugged.
When you tested the burner unit and pipes how long had the refrigerator been on? If only a minute or two then I would say run it longer like 30 minutes and then check again.
You would have to read your extended warranty carefully to see if the refrigerator is covered.
If you are not comfortable with Camping World you can always see if a smaller dealer will look at it. But since warranty pays poorly don't be surprised if they won't touch it if they didn't sell it.
You can always call a mobile RV repair person to come and inspect it. They will probably charge you for driving time and an your to look it over. And they probably won't touch fixing under warranty. But at least you'll know if it's fixable or needs to be replaced.