I would recommend you to join Sia official discord (https://discord.gg/sia) and ask you question there since there are more technical people that understand the inner working of Sia there.
If you execute Sia-UI from the terminal, you will probably see a segmentation fault error. This is because newer version of glibc breaks compatibility with some electron based app (Sia-UI is based on electron).
Make sure your wallet is up to date as older version of wallet is not compatible with the current chain. If you can find the TXID on an explorer, the transaction is completed and you will see your coins after you are fully synchronised to the correct chain.
Hi, don't worry, it's a bug. I've got the same issue since December last year. I've got hundreds of contracts (in fact, they are less, this is another bug) and some 200GB of data stored on my drive. However, Siahub does not see my host at all. I gave up, hopefully they will solve this issue in the new GUI version.