Mozilla gives me lots of trouble again and again

I have these problems that keep on coming back or are never resolved:

1. After I spent considerable time to set up my Newsgroups which I had 
under MS OE 6.x into Mozilla (all manually and very time-consuming) they 
are there for a few days. Then all of a sudden on sign-on they are all gone.

2. The same for the Mozilla specific Newsgroups. Very annoying, 
especially since on the main pages of Mozilla there is never a quick 
answer how to re-create Newsgroups.

3. I have never been successful to Import my Addressbook into the 
Mozilla Addressbook. It always imports into another,new Address book

4. I have Imported my Folders in MS Mail into Mozilla1.6 but the Inbox 
and the Sent box is always empty. Yet it is not in MS OE. That annoys me 
a lot.
I saw messages as to .MS files, but when I go there, they are non-deletable.

I like many things about Mozilla, but these things eat up a lot of time 
and I do not know how much longer I can spend on them before going back 
to MS OE.

BUT _ I am willing to listen.