You have ended the employer-employee relationship by tendering resignation.
You have resigned and you have not absconded.
Resignation can be without permission and notice.
You have not tendered notice pay in lieu of notice period if it is applicable to you as per service conditions applicable to you.
Non payment of notice pay in lieu of notice period does not imply that employee that has resigned can be termed absconder.
The charge is false.
The approach of the Bank is erroneous and transgression, and coercive.
It can go to court if notice pay has not been paid.
It should have supplied acceptance of resignation and demand of notice pay.
It has sent demand of notice pay and afterwards has changed its stance.
Approach an able labor consultant/service lawyer with all docs on record and let your lawyer submit a fitting reply.
Obtain service conditions that apply to your designation from Employees Union leaders and check if you are covered as 'Workman'.......................
Notice period/pay is part of service conditions and does not neccessrly depend upon T&C inserted by employer in any private agreement drafted by employer and signed with employee e.g. appointment letter............................