Hello and welcome to Frogville!
Gizmo is right, it often will take a day or two for the froggies to settle in and feel comfortable enough in their new surroundings to eat. . .I'm not sure exactly what you meant by 'aquatic frog and tadpole food.' but oftentimes frogs won't take the pellets that are made/sold for them - some do and some don't - it might depend on what they're used to. None of mine ever have
Do you know what they were eating at the pet shop? Most frogs can't resist a bit of defrosted bloodworm, so if they continue to refuse food for the next day or two, perhaps you can give that a try? Stay away from the freeze-dried stuff, you want the ones that are wet-frozen, almost every fish shop has a freezer somewhere and sells them. They aren't that expensive, and a packet will last you for ages.
Otherwise, what size tank are they in, and is it cycled? Do you have a water testing kit? If so, can you give us your parameters?
I don't know anything about shrimp, so I can't help you there, but like Giz said - there is so much info to be found if you go through this thread, so if you haven't yet, go through and read through the millions of pages here - you'll learn tons about how to properly care for your new little friends!