Bought a game play expansion pack and won’t let me use it!

It’s been a while because I haven’t wanted to make a problem about it but back in October I bought a gameplay expansion pack for my sister and she  played with it for two days and turned off the laptop the next day she got on it wouldn’t let her use the pack anymore. My sister has complained that she hasn’t been able to use it and I haven’t figured out how to report a problem like that until today. I want to know if there’s anyway to get it back cause I would really like to not have to buy it again.