sounds like you need to go back to the 8606 from your original contribution where the problems began...
"I over-contributed to a Roth IRA a couple of years ago, so I had to recategorize the excessive contribution to a Traditional IRA"
that should have established the basis in your IRA for the amount contributed
"I converted all of them to Roth IRA a few years ago and filed 8606. That conversion established a basis of $5575"
a conversion to Roth should have removed the basis in the Trad IRA, not established it.
if you have $0 balance in your IRA you have no basis.
