Re: I have a TX with 6928 confirmations but total balance is still pending
and a Bitcoin core installation v015.01 64 bit
Maybe you can try to install the latest version of the client. At the moment it is 0.15.1 (0.15.01 is older). Or try an older client for example 0.14.xx.
But always make a backup of your wallet first. Hope this bring your bitcoins back.
https://bitcoin.org/en/version-history