How do I get to download music with a different id when it comes up with the message cannot download for 90 days

I need to know how to do this as well because before I got an iPad I hot an iPod nano and an iPod touch but because I was too young I wasn't aloud my own Apple ID and I used my mums. Through those years I got a lot of iTunes vouchers and I spent them on films and music. Last year I got an iPad and was aloud to make my own Apple ID I've downloaded a few songs and films but want my films and songs from my iPods but when I log in to my mums account on my iPad and try to download films and music but it comes up with you cannot download this item for 90 days because you have been as scouted with a different account. But I really can't wait 3 months at the moment cause haven't watched this film for ages. Please someone help me this is unfair this needs to be changed how could Apple be so harsh