I recommend you to join the discord and ask for help if you are still having sync issues
https://discord.gg/wTaF6qZ. For me wallet works perfectly always staking a lot and never having sync issues really.
This was posted today on official discord by the dev, maybe it helps you:
Make sure you are using latest Wallet Release for your Operating System.
https://github.com/MONKEYPROJECT/Monkey/releases#1
Close the current wallet.#2
Navigate to the folder of your Blockchain.Windows:
C:\Users\YOUR_USERNAME\AppData\Roaming\monkey
Mac:
/YOUR_USERNAME/Library/Application Support/monkey
Delte all files EXCEPT! the wallet.dat file in this folder. Please double check that you got a copy or the original file of the wallet file. This file stores all of your coins. If you permanently delete thise one all of your coins are lost.#3
Start the Monkey Wallet again with only the wallet.dat left in your /monkey/ folder. The Chain will now resync from Block 0.#4
Wait til the latest Block is downloaded. Dont transfer any coins before you are synced or you got to repeat Steps 1-3. Double check if you are on the latest Block by checking http://chain.monkey.vision and your own Block (Debug -> Info -> Current Block)#5
When you are synced and still miss any coins or corrupt transactions please navigate to Debug -> Info -> Console and type "repairwallet" and press enter (without " " ). If you got a Wallet Pass True then all is fine. If you got a Missmatch message your chain will be repaired. it not help in me, i has try it.. best result... delete all only wallet.dat after that waiting snyc and waiting stake again (coin has stake be fail minted because this problem),,, repairwaller or checkwallet not working,,,