Byju's — They are not cancelling my subscription

This is Shakti.I had taken a subscription for my daughter for 3 years (lkg, ukg, standard1) for 60k.I had done payment through credit cards (5K + 55K).I took this subscription from a sales person who had visited my house.Honestly speaking i took this wrongly as daughter is just 4.5 years old and she was already having some health issues in eyes and body.So I thought to cancel and so i sent mail to the customer care for cancellation.In a day/two i got call from their team and they started arguing with me like why i cancelled.I tried to explain them but they were not listening atall.
Only lady called 'Anshu' from their team had called and she was arguing like anything.She asked me to give medical proof and she told at last if can not give medical proof then she will not cancel it.
I have called multiple times to the customer care and even i have sent mail to them, every time find people are so rude, they do not listen anything.Their simple agenda is NOT to return money.I am wondering what to do with these guys who do not listen anything and they do not have any respect for customers.Even I tried to call the person who had sold the subscription, he told like he can not help anything as I am cancelling .I feel so helpless now.