can content of text message be retrieved

Your query is not clear.  please post facts.

someone filed a complaint against my husband under section 420 ipc .He has deleted text messages of opposite party from his phone , now we want to retrieve the messages as those are the only source which can prove their allegations wrong

You are approaching the wrong forum. Contact your cell provider if it is SMS, or e mail provider or whatsapp as the case may be. In.most of the cases Electronic messages are not admissible in Courts as primary evidence.

You can contact any software expert and make arrangements for getting such data.  Whether it is admissible or not is a different thing, but you can atleast place them before a court as a defense.  Obtain those call record as certified copies.  Go through TRAI regulations available in their website as claiming such record is a right if you are the subscriber.  But, if you are not a subscriber and wish to get such text messages between third parties, you may not get the same and should approach Police for getting such data.  If it is relevant to your case and if the texts belong to third parties, you can contact advocate and issue summons to service provider for providing such copies through the process of the court.

Legally speaking, in criminal case, it is for the complainant to prove his case.

The first post is not on the burden of proof and is simple as follows: ' I want to get the content of text messages for last 6 months, is it possible and where I need to lodge the complaint.