Why can I not see where my data went.

I received a wifi router on the 28 of August. On Monday the 31 of August I put the sim card into the router and within 2 hours my data had depleted. I was on the phone with a number of call centre agents who were unable to help me, by this morning I received a call from an agent named Randall, with the most poor attitude ever. He then sent me a message that summed uo the call \ Good day