It's amazing what you can learn by not resigning if you are used to always resigning when things look pretty grim. One way to think about it is: if you are getting totally dominated by a player who is supposedly your own level, maybe there's a reason this player is not rated higher. Maybe he/she throws a lot of games in the endgame. There are an awful lot of players who aren't good at winning won games. They miss things when the liberties get short, or they just get tired and careless and don't have the endurance to play a long game. Maybe they get greedy when they are ahead and assume you are pushover. Whatever. If you resign too early against such a player, you're not getting a chance to exploit their biggest weakness. Although I like to think I have reasonable resigning habits, there are some regular opponents I have where I do something different. With them, I've learned to just be patient. 30 points behind going into the endgame in not necessarily fatal against them.

My question is, why did white continue to play after you passed... twice?!

It's an example of:
* Being way behind and not resigning.
* What a hint that you should resign looks like.