Byju's — Illegal allotment of course

I asked to cancel my byju's subscription of 11 + 12 JEE course, but they have illegally subscribed me to the course.
I did not even opt for the course and now every month some amount to IIFL Loan is being deducted.
I want immediate response over this and cancellation as soon as possible, plus refund of all the illegal amount collected as of now from the 11 23 jee course.