Non Payment of Dues

I am a video content producer running my business under a Proprietorship. I was commissioned to shoot a project for a industrial shoot through a agency in September - for which I demanded a 50% advance which was paid to me. Post that I completed my project and the final film was delivered to the client. From the past few months when I've been trying to close the accounts with the agency, but they have been claiming that they have declared bankruptcy. I clearly stated to them on mail to submit the appropriate proof of bankruptcy on this email to which I will proceed accordingly - and have given them a deadline for it. I receive a reply from the MD saying how sorry he is and all he responds is "the company has declared bankruptcy on April 1 2019, since then we have filed reverse invoices for customers and vendors for all outstanding payments. I am sorry to say but we won't be able to make your outstanding payment." To this is asked them to share the proof where they have filed for something like this. To which I get a reply "We have submitted the paperwork to GST office, I can only send it to you once we have received a copy ourselves. And we have already cleared the TDS for your outstanding payment with the tax office." As per the little that I know a reversal of invoice is not exclusive to a company going bankrupt or either does paper work at the GST office. I sense foul play in this matter. I would appreciate any advice as to how I proceed to this. Thank you