The 13.5GB pack is eligible only for subscribers in New Freedom 325 and New Freedom 375 plans.
Multiple subscription is not allowed and if you subscribe during the month, you will get partial data and partial rental for the first month (pro-rated).
Pack will auto renew on monthly basis.
In case of plan migration/upgrade/downgrade, the pack will be automatically cancelled, however, any remaining data in the pack will be available until the end of month.
There is no exit charge applicable for the data pack.