How can I check where my bitcoins have gone to in my app?
That looks like the unimaginatively named "bitcoin wallet"

I would review the transaction details provided by the sender of the Bitcoins. If you have a transaction-id or receiving-address you can look it up on a blockchain explorer to see what is happening.

A few obvious possibilities to bear in mind


insufficient mining fee
incorrect recipient address
problems with wallet configuration


not syncing with bitcoin network
private key not imported?