Common issues related to your wallet include the following.
I used the wrong wallet address for a transfer
Meso only allows you to use a wallet for which you have verified ownership by signing a message during onboarding and again when starting a transfer. Therefore, although the crypto may be in the wrong wallet, you can use the "Send" feature available in all wallets to move your crypto to the desired address.
For example, see this support article on how to use the send feature in Metamask.
The transfer was completed, but the crypto hasn't arrived in my wallet
Firstly, verify that the Meso transfer has completed. You should have seen a transfer status page on meso.cash after the transfer completed as well as received an email receipt. If you have seen neither of these then the transfer did not complete.
If the transfer did complete, then, depending on the blockchain, it can take anything from seconds to minutes before the on-chain transaction is reflected in your wallet. After waiting, be sure to refresh your wallet in case it does not auto-update to reflect balance changes.
You can also verify the transaction by viewing it on a blockchain explorer. Either by viewing the transfer status page on meso.cash, or, by looking at your email receipt, you can copy the blockchain hash (also known as the transaction hash) and enter that into the search bar for the blockchain explorer.
The most common blockchain explorer for Ethereum is Etherscan.
For Solana, try Solana Explorer.