Data contract suddenly changes

<p>During August 2016 I had excepted a mobile wifi contract offer (over the phone) that offered 10gig per month....come 2017 the contract was changed to 500mb...there was no mention of the down grade during my conversation with the agent...after numerous calls to them to try and resolve the matter no solution has been offered. I urge you not to except contract deals over the phone as key bits of information may be omitted.</p>