Byju's — not refunding my money

Address:

Bangalore, Karnataka

We received a call from mr. Shubham chaudhary of byjus. He told my parents that he will take my test and analyse me.
He also mentioned that he was coming from bangalore and will return the same day. He convinced my parents to purchase this package for me. But after 3 or 4 days, i didn't found it useful. I asked him on 10th day to help me return the tablet. He said ok and he will help me. But later he blocked my mobile number and didn't even replied my single message. When we approached the team, they said that its whole my fault. I even gave them my proofs but they just refused with no excuse. Now they are calling and saying that i would have to return the tablet without any refund otherwise the bank will charge me interest. Please help me. I have proof on my side. I wouldn't return the tablet without refund.