Monday
I have 100mbs of data, my phone won't connect to internet via data and I've only used 42 mbs
Monday
Are you sure you've only used 42mb? There could be a cache issue and the usage counter doesn't always update right away.
Monday
what phone do you have? Make sure your phone has the latest OS update.
Try reboot your phone first, then click Reset All networks on your phone
if you have an Android, make sure you didn't set data limiter on your phone
if you have an iPhone, make sure you have the latest carrier profiles