Thank you for your post, and apologies for the delayed response.
You are absolutely correct that the NSW Gas Rebate was introduced in July 2015. However, this was payed out as a lump sum on your first bill that was issued after 1 December 2015. This was paid out for all our customers who held a valid, eligible concession card from 1 July 2015. You can find out more about this here. If you did not receive this payout, please get in contact with our service team
who would be most happy to help, you can reach them here.
I hope this helps answer your question.