You should never mix frog species. It doesn't matter what the pets store did, it's a huge NoNo to mix. They could well be lethargic due to illness or just plain stress. Either way they should be seperated immediately. also, the humidity is way too high for the White's.

Here is a good care sheet for the White's.

http://www.frogfreaks.com/index.php?topic=70.0
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