Lady buy a air conditioner from us and promise to pay and now she is having a lot of stories

We live in Phalaborwa and having a small business, Some lady bored a 18 000 btu air conditioner from us for R3600.00 and she payed a deposit of R1200.00 on the 3rd of November 2017. She took the aircon and she promised to pay the ress of the money at the end of November 2017. until today she havend pay a sent and having a lot of story, can you please help us to get the money from her of the aircon. Thanks