You can file a civil suit in the court of law against your ex-neighbour and her company to recover the loan amount. The court will assess the evidence you submit and award a judgement in your favour. In case the defendant fails to comply with the court order, you can file an execution petition to recover the loan amount.
You can also file a police complaint against the defaulter for cheating and fraud. The police will investigate the matter and take the necessary action against the defaulter.