Day light *******

I checked for coverage prior to purchasing the sim card and the consultant called and assured me that my area has network coverage. I received my sim card but was unable to connect, 2 days later I cancelled it since it was of no use. to my surprise i was billed full amount month end when I didn't even use the data. i logged a request and to date no one has called and even worse next payment date is also reflecting on my account, how so????