Hello Bishal,
I'm sorry for the confusion!
We launched two programs this spring: one for students and one for professionals whose jobs were impacted by COVID-19.
The one you joined, for students, ends on August 31 as noted in the e-mail. We cannot extend your existing student account. There is however a new student program starting Sept 1 that you may be able to join.
The second program for professionals, which you did not join, is referenced in this blog post. This information does not apply to the program you joined.
I hope that makes things clearer.
- Adena and the Learn ArcGIS Team