Clarification Regarding Excess Ex-Gratia Payment from Employer

Hi, I seek the guidance regarding a legal notice I received from my previous employer. Background: Upon leaving my previous company, I received an ex-gratia payment. However, there seems to be a discrepancy between what was communicated by my manager and what was reflected in the Full and Final Statement issued by the Separations team. Here are the details: Manager’s Last Email: Date: 26-Mar-2023, Mentioned ex-gratia amount: Rs6,25,197 Full and Final Statement: Date: 28-Apr-2023, Mentioned ex-gratia amount: Rs18,84,893 Repayment Situation: In good faith, I promptly returned Rs598,576 to my previous employer in monthly installments. This decision was influenced by their refusal to clear my background verification check with my new employer last year. Current Challenge: Unfortunately, I find myself in a difficult position now. Having been let go by my new employer, I am unable to repay the remaining balance of Rs238,459. Recently, my previous employer sent me a legal notice regarding this matter. My Concerns: Can my previous employer legally pursue this case, even though the overpayment was not my fault but rather an error on their part? Moreover I have a Full and Final Statement, which shows the ex-gratia amount: Rs18,84,893 (overpayment of Rs. 8,97,150 credited on 28th April 2023). Am I legally obligated to return the excess amount? Thank you for your time and assistance. I eagerly await your guidance on how to proceed. Kind regards, Ravi