Byju s - cancellation of order

I want to bring your attention that i had purchased online classes with TAB for class ** CBSE.
TAB was delivered to me on **th May ****. Since classes were not good, we intimated on **th June **** about the cancellation of order via E-mail on your cancellation ID.
I send series of reminder E-mails and made calls date wise E-mails communication given below and screen shot of E-mail also enclosed for their reference.
Now their representative is saying that since you have not told mentor about cancellation over the phone we are unable to cancel the order.
On their website also it is asked to send E-mail on cancellation ID with in ** days which is i did & even i have send reminder well with in time.
Extract from web site
"A Refund Request will be deemed valid only if it is made through an email to cancellations@byjus.com or by calling us on +**-********** within ** days from delivery"
I am surprised to see such kind of unprofessionalism in their organisation and lame excuses given by person for non cancellation.
I think some mis management going on in their organisation or their organisation is cheating the customers by giving false excuses.