Corwin, Prince of Amber

Had to reformat due to worm or some Windows nonsense. Whole weekend
to reinstall OS, etc.

I've got my original Garmin SPIII info with a Unit Serial Number, an
Unlock Code (25 characters), and a Registration Code. But the Unlock
system won't let me unlock again because "the registration code has
already been used", and I don't know my "customer id" or my "coupon
code".

I have all the original paperwork and sales receipt for the SPIII;
what are the odds of getting help from Garmin to unlock the maps
again?