Atlantic City, NJ - Using Cricket Modem AC3781 attached to laptop - Since Wed 05-09 around 5pm EST.

I've been experiencing sudden connection drops after getting connected around the time listed, but my data usage according to the cricket site seems to have skyrocketed! Yesterday I seemed to have clocked in 133 mb for the day, when the connection log at the computer listed only 50 mb. These mega data usages seems to be the pattern since the last week until now. I'll definitely hit my limit by the end of this week if this continues. I've been mainly on Facebook updating a game from time to time, no photo uploads. The only thing I can think of is someone is stealling my bandwidth at this location, but I can't figure out how, since the modem gets ejected when I am off the laptop. I tried to contact customer service, but I got cut off when the operator tried set up some kind of "passcode" Been looking for some kind of explanation ever since. Thanks for any help you can give me.