fraud billing after closing connection and forced us to pay bill

I started using tikona services in April and closed the service in month of May due to shifting my place.
They said minimum you have to pay for 3 month atleast then your connection and account will be closed.

i was fine with that and payed for 3 month. And returned the device that they provided.

After 6 month i got a call from pennel court regarding unbilling amount of Rs. 1874. They threaten us to pay the bill and amount otherwise they file a case. And also suggest please pay the bill and after billing we will provide the amount to you but i haven’t received any amount back and they are not even receiving my calls.

My account details : Tikona Service ID No 1109940713 & Billing Account Number 121494237

Transaction details :
BAN : 121494237
Payment Amount (Rs Ps): 1874
Payment Date : 16-11-2014
Payment ID : 1-3279575652
Transaction ID* : 1109940713TPC1611141111893
Payment status : SUCCESS

Please help us to get the amount(Rs. 1874)