Due process in employee dismissal; necessity of formal hearing and cross-examination practice question

Maria, a warehouse storekeeper at a large telecommunications company in Cebu, was investigated for alleged anomalies in inventory withdrawals. The company issued her three written invitations to appear at separate formal inquiries, all of which she refused to acknowledge or attend. The company proceeded to terminate her employment for loss of trust and confidence, relying on affidavits and documentary evidence, without conducting a formal hearing or allowing Maria to cross-examine the witnesses against her. Maria claims her dismissal was illegal because she was not given a formal hearing and was denied the right to cross-examine the company’s witnesses. Was Maria's right to due process violated? Explain.