Night Express data issues

When I signed up for a data contract in November 2019, all adverti*****ts mentioned night data is from 00:01 to 5:59am. In January I noticed my normal ‘day’ data was being depleted between 5am and 5:59am. I sent emails to there complaints department with no response. Throughout January and February, I have been liaising with there Facebook team, initially, they said it can’t be, so I proved to them my data was being depleted. They then told me Night Express times have changes, I then proved to them with reference to their own website that Night Express ends at 5:59am. Nothing has been done since. Terrible service!