Anna University — Delay in issue of migration certificate and uncooperative customer services

I have completed my engineering degree from Mar Ephraem College of Engineering and Technology and had applied for a migration certificate on 4th december 2021 via speed post; and had received a message stating that the post had reached the destination on the 6th. All the necessary details and forms along with the demand draft were attached along with the post. My register number being[protected]. Till date am yet to receive my certificate and once I try contacting the authorities, the either don't pick up the calls or turn off as soon as they pick it, the numbers I tried contacting being, [protected], [protected] and [protected]. Am in urge of submitting my certificate as i am to complete my post-graduation and without the certificate I will not be receiving my degree.