So,
iPhone MMS you did not receive at all? Or did you find some bak files under .fmms/mms? Then they were received but could not be decoded.
But in the same time (same mobile service provider) you received other MMSs? But those were decoded (pics and texts under .fmms/mms) just the UI cannot show them?
Possibly picture format???

For your other "prob":
just use fAPN from repo (or delete manually from gconf )