Sims 3 pets xbox 360

I have the Sims 3 Pets on xbox 360, i have been playing a while and all has been fine up to now. However suddenly one of my sims has froze talking to my other sim and neither one will move or do anything even though they are both going to collapse soon nothing is happening! i have reset the game and tried to continue but it just keeps going back the the last point i saved which was when the froze. Is there anything i can do to sort this out???