what should I do if I need sylvia to advance the story but I don't have her in the store, I have done all the actions for her appearance in the store, I have Ashley I have 33 levels and sanctury I have built, also in the story I had her appear and yes in sanctuary she doesn't appear. ?
You do not say what version of game you are playing.
In general, just continue with the story. Eventually Sylvia is going to be available. There is a special event after which Sylvia is available.
If you want to spoil your game, the Wiki has description of the events. If nothing else helps you can see from Wiki what must be done before an event is available.