Byjus - Cancel my Byjus course and get a refund

Dear Sir/Madam,nI had enrolled my child in Byju's online learning course in march **** Byju's had put us on an monthly instalment payment schedule for the total course fee of around Rs.**,***/- I had deposited Rs.*****/- as advance with the balance payable in monthly instalments of Rs.****/-. Through my credit card .After just * to * months of the course, we realized that my daughter is not benefitting and she was not able to continuebecause of her personal reasons.. So, we decided to discontinue the course. However, Byju's were insisting that since we had not cancelled within the **-day period, they cannot cancel the ECS given by us. nMy daughter had not attended most of the classes in the * to * months and she will not able to attend the classes in the futureof . It is very clear that our child is not going to benefit from the course. I clearly explain ,I dont want the course and i want refund the amount to support team . But they continuously said they dont cancel and refund my amount.Please advise what I should do in this case.Thank you.