Work harassment

I reported work harassment to the HR of the company in the month of June. No action has been taken against that till now.further which I am escalating this matter to the top authorities. i.e. CEO, COO, Head HR..! For that I need to provide the call recording with concerned HR. Service provided denied to provide call recording for the month of June, which contains important conversation with the HR. Could you please advice how can I get the call recording, is there any law to get recordings post filing FIR..??