Disappearing data and bad service

Firstly I had over 3GB of data on my pad then that data disappeared without having used my iPad. I called in and was given a story a then given 2GB of data. I haven't used my iPad and I always do before use my iPad out wifi range I check my data bundles which should have been 4GB there is nothing. I have call the call twice now and on both occasions I get cut off when been placed on hold and those agents can't even called back knowing that had me on the phone while they looking up what ever they were looking up. This absolutely unacceptable I want all the data loaded back onto my device.