The major facility for salary accounts were zero minimum balance. The salary account can have zero money in the account and the service charge for minimum money for the normal accounts will not be applied. However due to the conversion from Salary Account to Savings Account, this zero balance facility is lost.
ICICI bank will start deducting money from account if the account do not have a fixed minimum account. Read the post on: How SMAB charges Wreck Your Savings Account in ICICI Bank?.
This service charge is called SMAB charges. Usually it is 393 rupees per month. The customers are not getting any SMS regarding this deduction.
If there are no credits to your salary account for few months, it would be better if you can contact respective branch and ask whether your salary account has converted into savings account. If yes, then ask for the minimum balance to be kept in the account and levied charges for not keeping minimum balance.
If already money is debited from your account, Kindly read below posts.
To know more about SMAB charges, read my post: What is SMAB Charges in ICICI Bank Means?
To know what can the customer do if money gets deducted by SMAB charges, read the post: Think Twice Before Taking Account in ICICI bank
You can contact https://twitter.com/ICICIBank_Care for resolving your queries.
If your Bank is HDFC, kindly read this