Jammu & Kashmir Bank / J&k Bank — sudden deduction as amb charges

Address:

Srinagar, Jammu and Kashmir, 190017

So yesterday i logged into my mpay app and checked my account balance. But to my surprise i'm finding that my account has been debited by 148rs as amb charges.. I don't know anything about this amb charges neither was i told about it before.
It would be really convenient to let people know first why they're being charged instead of suddenly debiting money from their accounts.