I can’t be sure that your coins have been stolen, that’s why I called it a „guess“.
I can only tell you what I see and that's a heavily reused address with at least one (more of that later) suspicious transaction.
Your coins have definitely left your CURBZI-address on December 16th and have then been split up into two parts.
If you didn’t do this, then someone else did it.
The missing funds on your input address(es) make the transaction unable to ever confirm, there's no doubt about it.
I didn’t have the time to take a closer look at your other address last time, but this one looks equally messy and has also been reused multiple times.
For your unconfirmed transaction to confirm a balance of 5 Gi would be required on this address: https://thetangle.org/address/JS9NDEAROSEPHMMBDHQAUTRRQNAMXJSMIKXNQDAWLHPFQXELUIIRDWFHOCJFSLDBNUIAIFSDTRXBZHZHW
But the balance is only 1.78 Gi and that’s because 3.22 Gi were sent away on December 17th: https://thetangle.org/bundle/FZDIFIDLLSJCUELLHOLN9GFJBHJEGOKJUI9VEX9XB9JJQLLBNRUZTDHSHKVBDBJSFGBCXVFS9XOICSLVW
You can see that 1.22 Gi went to this address: https://thetangle.org/address/DBORZHKSJOJOFJOE9ZNHTDXWVQAWOULJBSDYBDQFHBYBU99RQAYJUKHMXBNMOMNGXODJUSGTK9ZUASVKW
… which is another (!) reused address. But at least it looks like it’s one of your own and since it so far only has one outgoing transaction these 1.22 Gi are still there.
The other to 2 Gi went to (surprise) CURBZI….
They have arrived one day after the (potential theft) transaction and were sent away only five minutes later.
I'm not going to guess this time, but again: if you didn’t do this, then someone else did it.
I'm honestly surprised that those 1.78 GI are still on JS9NDE...after three exposures of 50% of the private key. Seems like you got lucky with overlapping parts. However, the funds on this address are at a very high risk of getting stolen whenever you make a new transaction and expose yet another part.
The error you’re getting now is a protection measure to prevent exactly this situation.
You now have funds on at least three used addresses and the wallet won’t let you send another transaction because that's very, very dangerous.
It’s a mystery to me how you even managed to reuse your addresses in such a way. The wallet should have thrown this error to protect you when you first attempted to send a second time from the same address. No idea why that didn’t happen.
Which wallet software were you using for your transactions?
This article explains how to fix your problem and hopefully save what’s left of your balance:
For Trinity: https://medium.com/@hbmy289/warning-funds-on-spent-addresses-how-to-unblock-your-funds-3a8d763f0a51
For the Lightwallet: https://medium.com/coinmonks/private-key-reuse-detected-what-it-means-and-how-to-unblock-your-funds-383eeb8ca036
Please read and understand the article, but don’t try to do anything yourself now.
Don’t give your seed to anyone and get real-time assistance on Discord’s #help-channel. Here’s an invite link: https://discord.gg/hgbDnBd
For the coins that are gone, nobody will be able to bring them back. I'm sorry.
The best you can do is to understand why this happened and learn from it.
I wouldn't be able to help anyone without thetangle.org-explorer. If you feel like you want to support its developer Mathieu Viossat in maintaining his service, please consider a donation to the address shown here: https://thetangle.org/about. Thank you!