Buyer gave deposit but know won't contact me?

I received a non refundable deposit ($50) towards the purchase of livestock. The buyer was suppose to make payments and the pay the balance upon pick up of the animal. I have not heard from the purchaser since receiving the deposit(approx. 5 weeks ago). I have called and left messages on her phone and also emailed her, with no response back. How long should I keep trying to contact her, before I re-list my livestock again?