Well, since the transaction can be found on the explorer, the transaction is completed and the coins are now in a wallet poloniex controls. Their wallet are in maintenance right now. Sia devs had released the fix for their issue, but it depends on poloniex when will they apply the patch and re-enable their SC wallet. If you are not in a rush, I will wait them to re-enable their SC wallet and see if my coins appear. If not, the only way is to contact their support team. If you really need the SC now, you may contact poloniex support now and see if they can help you. Unfortunately, not much can be done except contacting poloniex since your coin is in a wallet they control.
perhaps you got it a bit worng; SIA is serving as a gigantic harddisk distributed amongst a lot of physical nodes. Together they make up a decantralized, distributed back en for storing files. The current UI can upload and down load single files.
Any advanced utilization is thought to be brought by the community or partners,
For your case as back up have a look at the duplicati integration;
Sia's blockchain is currently 4.1 GB (as of block height 105,542). To begin using Sia, your client (either Sia-UI or siac) needs to download the entire blockchain. I've seen reports from several users that this process is very slow, so I'd like to offer a workaround to speed things up.
I took a snapshot of the blockchain at about height 105,530 and uploaded it to Mega. You can download this file and use it to bootstrap your client. Here's how
Shut down your Sia client (on Windows, you need to right click the Sia icon in the task tray and click "Quit Sia")
Open your Sia consensus folder (see the bottom of this post if you don't know where this is)
Rename consensus.db to consensus.db.old
Download the blockchain snapshot from Mega: https://mega.nz/#!waAVzbxA!ueAYbcC4MNhFHrBotpUmpsIJfDhTDN7CKN3BCdZQkkA
When the download is complete, move the consensus.db file you downloaded to your Sia consensus folder
Start Sia again.
It will take ~20 mins for Sia to reprocess the new consensus.db file but then once it does, you'll be synchronized with the network. It will take another ~20 mins to unlock your wallet for the first time. After the initial setup, opening Sia-UI, synchronizing, and unlocking your wallet should take <1 min every time.
Note: Once the new consensus.db file is confirmed working, you can remove the consensus.db.old file.
Not only is that not secure it defeats the purpose of running a full node which if i'm not mistaken the purpose of running a full node is to validate all transactions and verify everything for your self in a trust-less environment without relying on a third party.