Where has my DATA gone? It says I have none and I should have loads rolled over

[FrankieU]

My data has vanished, I should have an awful lot and there's none there where has it gone?

[PandJ2020]

From the help:

Data expiry dates / Balance lower than expected

Reminder: Unused data lasts for 12 months.

There's no limit to how much data you can save, but it automatically expires after 12 months if you don't use it. So, each month, any data that’s 12 months old will drop off your Sky Piggybank balance. We don't send any reminders for this.