The same was today morning for Poland ,Samsung add Beta Banner morning ,remove after 2 hours and now is again available, is look some problem with servers
I'm not sure this help change CSC for BTU ,Check Xda website maybe you will find solutions
My mate managed to register and had a software update come up on his phone, he didn't download it as he was out and about. Got home and update has gone from his phone.
Looks like something gone wrong somewhere.