If she refused with you once and got away with it, she will just keep refusing again and again and again until you punish her. There are two ways to punish her, much more effective then the other. Most effective: Bring your hand to your hip and smack her with a crop once or twice and turn in a few circles. The go straight to the jump and give her a smack and a cluck. Least effective but may work: Do everything up there except for instead of hitting her if your not into that just bring her to a corner. One is like spanking a child, kne is like putting them in time out.
Refusing, I assume you are talking about when it comes to jumping. If she recently had surgery and now you are having trouble jumping maybe there is something bothering her and could be why she keeps refusing.