How does Data Rollover work?
Monthly data allowance
Say, for example, you have a monthly data allowance of 6GB and you only use 4GB. That's 2GB of data left over this month that you could use.
So that 2GB you didn't use - don't lose it - roll it over. The data allowance you roll over is counted first and you have four weeks to use it up.
Next month's data
Your unused data rolls over to the next month, every month. Just make sure that you top up by €20 within four weeks to get your Data Rollover.