Tata Docomo — stoppage of outgoing services

I already have a recharge balance of rs.91 to my tata docomo number.. Still i receive messages everyday to recharge within 2 days otherwise outgoing services will be stopped and further after expiry of 2 days period rs.23 will be deducted from my recharge balance.

What is this, can someone explain. I already have enough balance as per my requirement why company forces me to recharge when i dont even require it.
Tata docomo kindly revert