So I booked BKK to HKG to experience Emirates first class. We then arranged a trip to get to BKK and back home from HKG.

weeks after booking I receive an email saying that we are downgraded from First to Business. Due to an aircraft change.

the only offered us money back or difference back between first/business. We made other bookings that have value and we planned this trip just for the fun of flying.

She couldnt offer any compensation. I have ro write an email. Any suggestions or previous experience?

For instance, in Europe you would receive back 75% if you accept the downgrade. I might cancel, but it costs €250 to cancel my connecting flights.