[Resolved]  Byju's — tab not working

I got the tablet + sd card for pcmb content for xi and xii std science for my son. The content seems okay. But the app had lots of niggles. The questions pop up randomly unrelated to the video lecture and then jump to a latter part of the video.
Called the cs number given to us. It was dead. Mailed to the mentor who was to call back immediately. That didn't work either. The number to sell the product was prompt to respond. Took my complain and was to forward my call to the technical team... Which as it turned out was busy and would call back in 24h. Not good enough if student needs immediate support. Overall not a very satisfying and trustworthy experience. Still in look in period. Very inclined to give it up.