Simple Question: Does Go Roam Around the World Extra 14 day add on Expire?

[Marcus3]

Going to India for 8 days next month.
I'm on a legacy Unlimited package and don't have any Go Roam passes so need to buy a "Go Roam Around the World Extra" 14 day add on. 

I will be going back again in 2025. If I buy a 14 day pass and use 8 days, will the 6 days still be available next year say or is it a "14 day period" once the addon is activated when I land?

[MZone]

Once you use any of your normal allowances in India the 14 day pass will activate and the 14 days will start. Unfortunately you can’t bank any days if you used less than the 14 days. 

[Marcus3]

Does this forum give official answers or is it just customer-customer feedback?
I'd like to get an official answer from Three.