With the camper sloped to the rear you can hold it up with only one front jack. It is a lot of strain on that jack due to the angle and weight and that single jack may not be able to raise the camper any higher.
In Anne's case, she needs to shore up the corner with the bad jack and remove it. If she needs to move before getting a replacement or fixing this one, shoring up a back corner and moving a rear jack to the front would get her on her way. There is no use further speculating until Anne responds with her course or action.
