Based on the OP, it looks like it's your Private keys that are missing some characters.
Anyways, for the address, try using
www.walletexplorer.com.
It has an auto-complete feature for the partial address that you will paste on their search box,
the catch is: the address should at least been used once (
and not recent) for it to be registered to their database.
Example: if you search for "
1BitcoinEaterAddre", it will automatically redirect you to "
1BitcoinEaterAddressDontSendf59kuE".
More characters means more accurate search.