Byjus learning - Byjus NEITHER CANCELING NOR Changing Tab and not LISTENING THE COMPLAINTS

During lock-down time i received call from byjus regarding tab-learning program. I refused to purchase the program then again some another person some another canceller(Faisal khan
**********) called me and told me "Please order the product, It is very useful due to corona environment and if you are not satisfied then return it within ** days" Then i booked the program (class *thto **th) on ** May ****. I Asked for Samsung tab and they send Lenevo tab (without invoice and warranty card) having mistake in screen. Then i send complaint and when i called him over phone they keep saying "we will soon send the Samsung tab & sorry for delay its due to corona and work from home" then i also sent ** reminders via email then warned him to complaint in consumer forum even then they did not reply properly.
I also filed complaint in NCH (*******, ****-**-**) but they did not replied to them.
Torture and Harassment - They keep calling over my son mobile during his school online class, The keep calling me on daily including Sunday & Holidays. They send lot of sms for EMI ro me and my son. They also feared me for downgrading my civil score and no loan in future. They called email from Byjus and when ever i remind him about my cancellation/refund/tab change email they suddenly say they are calling from loan department not from cancellation department.
Half a year of my children's study has been disturbed due to byjus service/product.
Monthly EMI is deducting from my SBI account.They want only remaining EMI no service.
Please get replace the tab or refund the deducted amount also provide compensation to me. Also impose penalty to Byjus.
I have checked over internet there are many customer/student have complaint with byjus refund/cancellation/service.