sync not working

I bought PM and loaded it on both my iPad and iPhone. I additionally purchased the in app sync function for an additional 3.99 EUR, but it is never working. I tried all tips on catamount forum etc, tried to work around with file sharing, still with no result.
This is frustrating as I paid for something that is not working. Please do update or send a how-to-solve.

melasch17 about PocketMoney - checkbook, budgets, expenses, v3.1.9