Please, I need help. My wallet is not fully syncing

I could use some assistance with my ltc wallet. I still have not been able to figure out what to do to get my wallet to fully resync since he upgrade to I can see my coins but the resyncing progress is stuck at about 84.83% completion, 37 weeks behind. I’ve tried to delete the wallet and reload a new wallet but that hasn’t seemed to work. I made the mistake of trying to upgrade to the new version of the wallet after the deadline last year, but followed the instructions for updating for before the deadline not after.
Any help would be greatly appreciated and if successful resolution and full use of my wallet occurs due to that help, I will reward supporter with at least one LTC from that fixed wallet.

Blockchain database could be corrupted. What platform are you on: windows/mac/linux?