When you say the leveling system isn't working properly - let's define 'properly' a bit more. Is it not working at all? Is it an auto leveling system that isn't level when it finishes? Is one of the jacks sticking? We'll need a bit more info on this one.
You probably have two battery disconnect switches (on the forum they are often referred to as a 'salesman switch'), often found near the entry door. Make sure both of those are turned on (letting power through). Depending on how it's wired, when you turn off this switch you separate the battery from the charger.
Also, check your owners manual, or download one from online. It COULD be that the chassis battery doesn't charge on shore power, in which case you may want to add something like this https://www.lichtsinn.com/rv-parts/trik-l-start-view