[Blueface]

Sounds like you had a phone issue that was warranty related but you attributed it to network problems at the time. You are now out of warranty.
Apple is quite clear about the one year warranty and cost to talk to them after that.
Same goes with Dell, HP and any other company I have dealt with. This is not isolated to Apple alone. They all do it.

Not sure why you lost all data. You can do a restore and then sync all your original stuff that you had in the phone backed up, prior to the restore.

As for slowness, there is no doubt some folks are experiencing issues with the new 4 OS. However, on the new iPhone 4, it flies. The phone is quite quick for all applications.

Go back to the 3 version of OS and you should pick up speed again.