Welcome to AF! Do you have an automatic or manual? Does the cruise go off if you hit the brakes? If a manual does the cruise go off if you depress the clutch?
The deactivator switch could be bad about shutting the system down. A loose or binding speed control actuator cable between speed control actuator and throttle body could cause the symptoms you are talking about. A binding cable will cause all the problems you have. It is easy enough to replace or lubricate with WD 40. A new cable would be the right way to go.