You can Pay march-2017 Contribution before the due date i.e 21-04-2017
For the Previous Months you have to file in the respective months
After Belated Receipt of Payment, ESIC will revert to you with Claim for Interest & penalty
Since you have not paid ESI Contribution from the past 11 Months all Employees will not be eligible to get the benefits provided therein.
It is better to pay Monthly Contributions before the due date
Otherwise, in case of Employment Injury/Death etc you as Employer have to pay the benefits to the Employee concerned.