Think & Learn / Byju's — problem in return/cancellation

Hi, i have purchased tab against order id[protected], after sale no support has been provided to my child, as there representative told me to give support and help my child in her studies.
No follow up has been taken by concerns. When i inquired and ask for cancellation the order no gentlemen reply came from there side.
I have mailed for the same several times but till date no cancellation has been processed.
Instead of doing cancellation we have received several phone calls from them but till date no resolution provided.
No steps has been taken from your side, not you have updated me what action you are taking. This is totally misguidance and negligence being done by you.
Also i found absence of customer support and satisfaction.
Kindly resolve it till monday eod on top priority.
Now i am being suffering from mentally tension.
Harassment done by byjus, my experience is pathetic