Byju's — 11th 12th course product want to return but not getting any response,only they call for asking money

I bought the 11th 12th course for my child, and i didnt got what i was promised, there is no mentor support, we dont get a call back, its total money waste, i heard from manny people how they manipulate you to pay huge loans for a 2rs product, i only get calls from some unprofessional people for money, i mailed 100times, please help me to get cancelled this product
Registered email-arun.[protected]@gmail.com