I had the same problem with a 4-sector booking which initially showed availability in J, then offered only Y in one of the long sectors when I went back to book it - then opened up in J 2 weeks later. When I went through Customer Services in the UK, they wanted an extra GBP 500 to change that sector to J despite that fact that I went back to the website which gave me a price for J in all sectors that was lower then the original J-Y-J-J reservation. Then they wanted to charge me to cancel the initial ticket when I cancelled it and booked the cheaper option. Needless to say a complaint e-mail followed (still waiting for a response) and they backed down on the cancellation charge but I get the distinct feeling that there are more than a few bugs in the system at the moment...but that said, the EK website is waayyyy easier to use than QR or EY.