By the sounds of it you've not done Dead Phone Flashing. Follow these instructions.
1) Goto File -> Manage Connections. Make NO CONNECTION the top priority, click it, apply, then close.
2) File -> Open Product. Select you're phone model. 6280/6288 is RM-78.
3) Flash -> Firmware Flash
4) Select the Firmware File that you need. Click Dead Phone Flashing box, then click Flash or Start or whatever the button is, I cant remember.
5) Phoenix will then say "Testing Communications 1 of 40. Press power button" or something. When this happens, press the power button on the phone. Flashing will start once the dumper is put on the phone.
It may take a few tries to get it working using dead phone flashing, you may get an error that says "Unable to get error message" or something. If that happens, just try a different 5.91 package.
Cheers!
EDIT: I should add that after Dead Phone Flashing is complete, you may get an error that says Verification Failed and the phone screen says Test Mode on it. DONT WORRY! The flashing is actually complete! Take out the phone battery and put it back in, and turn the phone on. It'll work
