I would say just wait. Either she decided to keep it - or it is on it's way back to you. Just wait and see if it arrives, but definately don't reimburse her until you have received the bag and it is in the same condition that you sent it (and it is the same bag!!)
Be careful with this one, I hope you are on Paypal with this, buyer has to provide a valid tracking number which you or Paypal can track, otherwise you run into fraudulent buyers with fake tracking numbers claiming they already sent out the item and demanding a refund. Bottom line is if Paypal cannot track it, they won't release the funds to buyer.
I have one a buyer now who was supposed to return an item over a month ago for a refund and never returned it. Just yesterday I get an email from paypal (40days later) that the buyer has opened a dispute! I figured he decided to keep the coat, now he is saying it is torn!! I would just keep money set aside for the item just in case