Maternity benefit is a statutory right and it cannot be recovered just because the employee failed to rejoin after its expiry or chose to end the service contract. As you resigned, you were only liable to pay the notice as per the employment terms and nothing more. what does your appointment letter say about notice?
I suggest you meet the management of the organization and propose your candidature for an appropriate position.
You people take things for granted and leisurely discuss as and when convenient. I may sound harsh but I wonder why & how many, that too educated lot can't do right thing and right time? You just now thought of resuming your career after 2 long years and your liabilities of unsettled NP. What stopped you discussing all your decisions when you were still on ML? Why didn't consult your colleagues/HR or friends before resigning. You said, you were actually into 5 months of ML when you resigned. If I'm right, you were entitled to 26 weeks of ML (roughly 6 months) you could have rightly availed full ML and followed up with/extended with other leave like sick leave if you weren't in a position to resume. Even if this extension was not possible you could have thought of 'LWP' till such time good enough to rejoin. Of course it cannot be undone now. OK you resigned, you should have settled the NP as stipulated in your terms & conditions of apptt. There is no logic in saying one HR says this the other one said differently. There is nothing to interpret if & when the terms are clear. None of us here will be able to say categorically whether or not you'll be taken back. May be or may not. We are only outsiders. You have to visit your HR and explore the possibilities. Mind you, you'll have to, in any case sort out NP issue before hand. By chance you already obtained a relieving letter or acceptance of resignation probably that might help you seeking a job elsewhere also. Try & make a beginning, be positive. All the best.