Marriage cancelled but groom not cooperating for settlement

Marriage of my daughter was fixed on 25/11/2016 and engagement etc.done on 01/07/2016 at groom's home. Items worth more than Rs.4 (four) lacs including gold & silver valuables were handed over during the occasion. But due to growing dowry demands day by day on the part of the relatives as well as from the groom, we were compelled to cancel the marriage, on the request of the bride. This was informed over phone as well as through email to the groom on 29/08/2016 and he was requested to fix a suitable date & venue so that we can exchange our items handed over and settle the issue peacefully. But the groom is going on imposing various conditions like cash compensation etc. Despite our repeated requests over email & phone he has failed to intimate us the date & venue of settlement till date. Now it seems that he & his family are not interested to settle the issue peacefully and want to harass us by holding our valuables. We have relevant photographs of 01/07/16 occasion and all conversations in this regard made through email. The groom is also sending hateful SMS to my daughter. Please let me know as to whether emails can be considered as legal proof/ exhibit. Can you please guide me as to what can be done at this stage. I hope you can understand our mental stage now.