Refund for unused Premium Subscription (moved to a Family Plan)

[Family5]

My husband recently started a Family Plan and sent me an invite to join.  I already had a Premium Subscription and wondering if I'll get a refund for the remaining period of my Premium Supscription (13 days)?  The change over to the Family Plan happened immediately but I can't find anything now that talks about getting a credit back for the unused portion of the Premuim Subscription.