Have you ever deposited a currency in one of the sites or exchanges and did not receive the currency in your account. I means that the withdrawal was already done in your first account but did not reach your second account on the other exchange and remained on the network. Is this possible? What can be done?
It is possible. About what currency you are talking about? Bitcoins? Also, what are the exchanges you are using? Why not you add these specific things here so that people will try to help you exactly? I understand that you are talking about bitcoin as you are able to see on network, it may take time to get confirmation and after the required confirmation, it will be appearing on your account of your second exchange.
Hope you are aware of what is confirmation in bitcoin transactions.
You may check your deposit history on your second account for reflecting the deposit you are worrying about.
You must learn about the practices of your second exchange on required confirmation on different cryptocurrencies. Typically exchanges may get your deposited completed after 3 to 6 confirmations. For every services that you are going to use with cryptos, make sure about their policy on required confirmation before depositing with them.