spamming and harrassing

For the last 5 days, I've been getting non-stop calls at night from unknown numbers. I block one, he calls from another. Calls, messages, video calls 2 to 3 at night. Even after filing the cyber complaint, the calls are still coming. The scary part is how much he knows about me. He got my number through Telegram even though my number is hidden. He also has my email, my parent's phone numbers, what I do and my personal details. He is now calling my parents too. We don't know how he got their numbers. He claims he works in IT in Bangalore and has personal information of many other people as well. This suggests he may be involved in large-scale data misuse. I filed a cyber complaint already. Tried the helpline, it didn't connect. I don't know what else to do.