WHERE DID MY Q-MILES GO QATAR?

I have been a member with Qatar since 2009, when I booked my first flight to the UK. I noticed today, after booking another flight in September to Scotland that my QMiles have decreased from 48 384 to 24 720! Where did my miles go? I wanted to upgrade later for the Sept flight, to spoil my husband for his 50th birthday. Now I cannot. I have e-mailed Qatar Airways, but have still not receive a response. It is unacceptable to loose so much QMiles! I will cancel my membership, if not given the miles back Qatar.