BB Software :: Contacts Disappear After Yahoo Sync?

i recently switched phone providers from ais in thailand to t-mobile in the netherlands. shortly after, i decided to activate my ymail account on my bb and, of course, synced my contacts. before i get to the problem. i had one issue earlier already, regarding address book contacts that were sent via bbm. i couldn't erase them, ever. i did tried removing the battery as suggested in other threads but it didn't work.anyways, what happened shortly after the ymail sync is that all my contacts disappeared, while the contact that was not erasable multiplied. i have it about 10 times now. in addition, this error message turns up on startup:

uncaught exception java.lang.NullPointerException

i looked around in other feeds but couldn't find a solution. i checked the address book filters (they are all off). when i chose address book >> options >> ...@ymail.com it appeared that all my contacts still exist on the yahoo server. i just can't access them for some reason. i downloaded them from yahoo for now. i'm sure there is a way to import them but i started worrying that my device software might be corrupt.so, before i start looking for a solution to reimport the contacts, i would like to know whether anyone ever experienced the multiplied contact error i have. because having 12 identical contacts that i cannot erase in my address book is kind of annoying and i would wipe the device before reimporting the contacts if there is now way to delete them.