Evidence

before filing anything. contact someone legally so that each and every aspect is covered. you look under some different circumstances. and you should get detailed counselling on all the legal issues.

please contact a lawyer and WhatsApp support. all personal details are not revealed and are encrypted. thus it wil take a lot of time to retrieve it.

no any person entitled to get call details and whatsapp conversation of others,its only matter of investigation so only investigation agency have right to get it.and it's only circumstances evidence so not admit by the court without exact evidences

It seems your problem can not be resolved on your own. Better you get a counsel.