TRUECALLER PAY - Money deducted wrongly and not even refunding

I took * days demo of truecaller premium subscription. It was mentioned that I can cancel the subscription anytime in these * days and I won't be charged. I cancelled it a day before the * day period ends. Still the next day I was charged and my subscription activated. When I contacted the helpline singh they might be having any technical issues fir which they charged and renewed my subscription even after I cancelled it, they straightaway denied to help. I mean this is looting the customers.i need that subscription to be deactivated and my money refunded