why am i been locked out of live video.

now i backed a horse and the bet disappeared into cyber space,race starts so i go into currant bets and try to cancel bet ,notice comes up that i cannot cancel sp bets,(i on cancel at the off)then i try to view race live video disappeares ,horse wins and then my stake comes back into my account,the bet was cancelled.

for feck sake betfair what are you at.sort it out.