Voice Recording and Emails are valid evidence, but its upto Judge and how you present it. it will be supporting evidence, and judgement will not be based on that evidence only.
Lawyer can represent her to send Notice, on her behalf. but RCR notice comes from Court Registrar, not from Lawyer. your notice may be Lawyer Notice.
From your side no need to write letter or argue on notice served or not, your lawyer can just ask Acknowledge of Notice served to you. They have to shwo the Proof. Court can serv notice, if you are not found they can give in New paper too if Court Agree, that make you are absconding and deserting her.
If you can prove that she left you, wihtout valid reason and if you have proof that she flirting and said she do not want to come back then you can go for divorce.before she file any 498A or DVA, which make all those women supporting gender biased cases less effective.