Sims 3 pets won't work

[superstargirl808]

hi my problem is that I bought the sims 3 on steam and it works then I buy sims 3 pets and island paradise from Walmart and it says I never bought the sims 3 

[roberta591]

@superstargirl808  Steam installs the game differently and you need to contact Steam support on how to install expansions packs.