Having second thoughts - Store Clerk Cascades Employee Review

Been with the company for about 3 months. It sounded too good to be true. The job description is very vague. The position is definitely misclassified under their maintanence department rather than being a part of shipping and receiving. As a salaried employee I know staying late is a part of the job, but I have been expected to wait around and twiddle my thumbs for an hour after my shift ended to unload a trailer. I understand if the trailer shows up around the time I leave. But to make me wait when the trailer isn't even there, and then also the time it takes to unload it. That is being taken advantage of.