Did you tried to dump the private key of the address(The unspent address) using console and this command
dumpprivkeyCan you try this command line in the console below.
validateaddress "address"
To check if you own this address
it should show something like this below.
{
"isvalid" : true,
"address" : "1umybitcoinaddress54321",
"ismine" : false,
"account" : ""
}
If the 'ismine' shows "false" it is not your wallet address but if the result is "true" you own that address.