Byju's — Charging extra

I have byjus package with tab .from sep 2020 installments of ₹2750 were started.I pay through HDFC bank app.But now when I noticed my installments detail.I found that At 7or 8 of every month from starting I.e.september 2020, ₹2750 have been deducting from my account automatically even I never opted for auto bill payment.From September 2020, I have been charged doubled.from sep 2020 to March 2021 means 7 months × 2750. So plz refund my extra sum that has been paid to you.and stop auto bill to my account