I took a flight last week from BHD - SVG and order Economy Flexible, however I ended up with S class from BHD - LHR.
On my confirmation it stated class basis Y for both legs. Because of S class I ended with 300 miles short and sat at the back.

Has this happened with anyone else? paying for economy flexible and getting Economy?

Do I have the right to get a free upgrade and 300 miles awarded?