Here is the forum post that talks about how to fix synchronization problems. It is geared toward multi-location pos installations but they also apply to island synchronization. It sounds like you can skip to Step 3.
If a RECON service keeps stopping, then you can set the properties of the service and set the recovery properties to restart the service after the first, second, and subsequent failures. You can try setting Reset fail count after 1 day and restart service after 1 minute.
If you need us to do additional troubleshooting, just call into technical support and they will be happy to help.