Employee is on leave since 15 days - after show cause notice she immediately reverted back with her resignation

Dear All, One of our employee is on leave since 15 days, she shared us a mail before 15 days mentioning that she has some kind of skin related problem so, could not come to the office. After that we are continuously trying to reach her over call, whats app but she is not responding. On 26th Feb. 19 we have dropped her show cause notice and she immediately reverted back with her resignation.
Due to her absence we are facing problem as she was handling our clients and didn't given handover.
Question is:-
1- What should be our next step for the same?
2- We should give her documents with her salary?
3- Can we take legal action against her?
Please help me out with your valuable response.

You should send a regd.notice to report immediately and say she should hand over all the properties of the co. and complete the formalities of exit, till such time her resignation is with held. Also mention therein if she's not reporting within a few days a police complaint with the police would be regd. and all payments to her is withheld. If nothing happening you can initiate legal action against her.