draw in blitz chess

Today I played a blitz 5 minute game in which the position had repeated itself for more than three moves. I offered a draw but my opponent kept playing and I lost on time. Is there a way to claim a draw in this situation as you would a normal game?

When a position is repeated thrice, a player can click on the "Draw" button and claim a draw. No matter how unbalanced the position may be, the draw does not have to be unanimously accepted. I think that you must claim the draw on the third repetition of the move, not afterwards, to be entitiled to claim a draw.

That must have been very annoying! 

Pretty sure you can claim any repetition, three or more (not just at three).  So...there probably was some small difference you missed.  You could show the game and we could check.