If the outlet is actually working and the plug is fine, it makes sense to check the power cord itself - sometimes the wire gets damaged, especially at the base of the plug or near the multicooker's body. Bend the cord in different places and wiggle the plug a bit: if contact gets restored somewhere and the device shows signs of life (the indicator lights up or you hear a sound), then the problem is definitely in the cord.
Seven years is not an age when you definitely need to replace a multicooker. As mentioned above, replacing a fuse or fixing the power supply unit won't cost much. But before taking the appliance to a service center, it makes sense to search online for your Redmond model's manual - it sometimes describes diagnostic methods or even lists the warranty center's number. Many manufacturers indicate exactly where the fuse is located, and some people replace it themselves, though that's at your own risk.