Nokia Navigation :: Lost All My Map Data In C6-00

Not sure if anyone experience this problem.. I lost all my map data after I update the Taiwan map when I was in Taiwan. The reason is I was forced to update the Taiwan map again when I was in Taiwan.Before I travel to Taiwan, I have updated several maps, included Taiwan map in local.

When I used GPS in Taiwan( I use Taiwan paid card to make call), no map was displayed and I was very puzzle and annoy because I thought I installed the Taiwan. I tried whole day, and tried to get it worked but failed.I used hotel's wifi to check the map and was prompted to update the Taiwan map again. Puzzle.. but update anyway. It worked when I traveled around Taipei.

Now the problem come... When I back home here and no maps were shown, except the Taiwan map!! Again, I went online to download the maps. It wasted my efforts and time to download the maps' data.

Here is I want to know;

1) Do maps' data store inside my phone when downloaded?

2) If so, why I traveled aboard and the maps will not display except the local(singapore) map?

3) Even though the maps are free for download, but I have to buy data plan from other countries when travel. I though the maps can use globally?

4) Will 3rd party GPS works in my C6-00? For example Garmin, if nokia maps are not reliable.. Not sure if anyone experience this problem.. I lost all my map data after I update the Taiwan map when I was in Taiwan. The reason is I was forced to update the Taiwan map again when I was in Taiwan. Before I travel to Taiwan, I have updated several maps, included Taiwan map in local.