Write a letter to the Regional Provident Fund Commissioner concerned, under Right To Information (RTI) Act, asking him to provide the details of the refund made, or if not made, reasons for the same. Affix a Court Fee Stamp of the value of Rs. 20 on the top of the letter, and mark the application as 'Request for Information Under RTI Act'. Send it by Registered Post AD, addressed to the 'Public Information Officer', Office of the Regional Provident Fund Commissioner, ..... (Full Address). This should produce fast results. If you do not receive a reply within 30 days (I bet you will), appeal to the next higher authority.
Please keep us inofrmed of the result through this forum.