Byju's — Cancelation and refund of order no. 3375

I bought Byjus trial pack for class 8 on 25/03/2021 via my transaction ID [protected] but I don't received any OTP as my registered number is of Thailand to start my learning.
I wrote an email regarding this problem at [protected]@byjus.com on 28/03/2021. They give the reply that they have arranged a call back from concerned department within 24-48 hours and my request ID is 16458887 but no call back had received till date.
At the time of purchase they mentioned that you can cancel the request within 7/15 days so I decided to cancel the service and wrote an email at [protected]@byju.com on 31/03/2021.
A reply on 01/04/2021 has received regarding email that your request forwarded to concerned department and they will reach you shortly regarding the same but no communication had received after that.
Please arrange to cancel the order and refund my money.