There are many ways in which you can check your bank balance. Banks have been sending regular SMS notifications, push notifications and emails to notify their customers on their account balance. Your bank or financial institute might also have a missed call service, where you will be provided with a specific toll free number. You can call that number to check your account balance.
Your bank might also have a facility where you can send an SMS to a number given on your bank website for checking your balance. Make sure to send the SMS from your registered number. These services are free of cost.