What is the process of recovery if husband refuses to pay maintenance.

We filed a case of maintenance for my sister, where her husband removed her from his matrimony house for dowry of 10-Lakh and a Car, when she was 4 months pregnant. We spend around 15Lakh at the time of her marriage and fulfill all her in-laws demand, But her in-laws kept her all her stuffs and ornament in there custody. Post filing the case in 2016, On 16th-May'17 Family court ordered for interim maintenance of 15K for My sister and 10K for her daughter, Its being around one year he has not paid a single penny. 2-DW has already issues by family court, But police returned the DW saying, His mother told he is not staying in her family house and she produced the will by writing on nagar-nigam pad that he has no right in the family property now till her mother is live. So police is not able to execute the DW, Whereas he is attending all the dates in HC which he filed for stay order against maintenance with his brothers. What is the process to speed up for the process of court and police get the recovery. Please guide.