Amaron — Battery is in warranty period but not changing my bike battery problem occurs again n again

I have purchased amaron battery from arora dealers uttam nagar.
For my royal enfield bullet classic 350
After 2 months battery down problem occurs and bike self start not working
I go to shop as my battery is in warranty period for solving the problem.
They charged my battery and give to me.
The same problem occurs in 1 month
Battery goes down and not charging
So I go the shop but they are not changing my battery.