Byjus — Failing to provide me refund for my course

Website: byjus.com

I have enrolled the byju's gate mechanical course on 1st september and they told me i can opt for refund within 15 days and i paid 3000 indian rupees and i didnt like the course and asked for refund on 5th of september through E-mail and also contacting cancellation and support team of byjus everyday they keep telling me i will receive call in 72 hours but didnt received call or mail from them but i keep getting bot calls telling me to pay my EMI and i received call on 25th of november and telling me they cant provide me refund and they didnt even send me tablet and books which they promised before.
please help me sir
i want to cancel my refund and stop the mandate