Issue In Marriage

We tried convincing parents 2 years, due to pressure We got married with help of a lawyer. We are inter-religion couple. We registered in Tamilnadu marriage act. On the morning of the registration day, lawyer shows us papers like conversion certificate and invitation like marriage happened on so & so place with registration copy.  They got signed from us on those documents. After the registrar signed we got our Tamilnadu marriage act registration certificate on the same day by evening. We informed & shared marriage certificate to parents to make them believe. They gathered all the documents from that using influence and threatening us that those are forgery documents which ever submitted because there is no place like that to get conversion certificate which is mentioned in conversion certificate so they are blackmailing our life & carrear will be trouble if they file complaint. Please help us with solution or guide us how to void our marriage certificate and register in special marriage act?