If you are a Jio customer, go to 'my Jio' app and click on the know more option on the regulatory notice, you will find a link to a short video which explains about the Jio IUC charges, below that there is a link for the long 7 minutes video, click on that and scroll it ahead to the 6 minute 20 second mark and you will hear the Jio spokesperson clearly say that once TRAI removes the IUC charges and makes it zero, at that point whatever unspent talktime balance will be left in the account of the subscriber will be promptly returned to him in full. I'm attaching a screenshot of the official video for your reference.