Elizabeth, All the advice you have been given - especially by Bob - not to try to effect the repair/replacement yourself, is good! Don't attempt it is also my advice............

If you wish to change the tempo until such time as you can get it repaired, you could also use the 'Tap Tempo' button - not quite as easy the wheel, but with a little practise it can be done......... Just tap the button at the tempo you feel is right for a particular song/tune.