I got 22 confirmation for Bitcoin not up 50$ and still unspent ,ow can I get it reverse back ,it more than 4hours
I got 22 confirmation for Bitcoin
22 confirmations of a Bitcoin transaction mean that transaction is certainly beyond any economic hope of alteration or invalidation.
not up 50$
I don't know what you mean by this but will assume you mean the transaction was for an amount that is currently equivalent to USD 50. That makes it too small to be worth much effort to recover, you wouldn't spend 1000 USD to recover USD 50.
Someone knows the private keys associated with the receiving address. That person can create a new transaction sending the money back you - less Bitcoin transaction fees etc.
[h]ow can I get it reverse back
You can't reverse a Bitcoin transaction.
Under some circumstances you can invalidate an unconfirmed transaction if you act quickly enough and are sufficiently knowledgeable. In your case it is too late.
old generated address in nairaex
Since NairaEx is a Bitcoin exchange in Nigeria, you should ask them for help. It seems likely that they control the private keys associated with that address and are therefore the only people who can assist.
I'm not sure what you mean. Do you mean the transaction is still unconfirmed? In that case there are two options.
1) If the original transaction was replaceable (depending on your wallet this is something you can set with a checkbox) you can use RBF (Replace By Fee).
2) If you cannot use RBF, you can try to double spend the original output(s) with a significant higher fee to convince miners to mine the 2nd transaction before the 1st, making the 1st transaction invalid.
If your transaction is already confirmed, than you will need the secret key of the old generated address to create a new transaction from the old address to the new address.