Card deposit availability depends on your country, as not every region is supported. If a debit card deposit ends with Deposits aren't available in your region yet, card deposits are not available to your account right now.
Other failures have other causes, even when the sheet is titled Deposit Unavailable. Those are in https://help.fomo.family/en/articles/14728486-why-did-my-card-deposit-fail.
If your bank is showing a charge from a failed attempt, that is a temporary authorization hold. It was not collected. Your bank releases it on its own, usually within 1 to 3 business days.
You can still fund your account by depositing USDC.
If you already have USDC on an exchange or in another wallet, open the app, go to Deposit, then Crypto, pick the network your USDC is on (Solana, Base, BNB Chain, Monad, Ethereum, Robinhood Chain, or Arc), and copy the deposit address. The screen shows that network's minimum, if it has one.
Send only USDC to that address on the same network you selected. Robinhood Chain is also supported; there the deposit asset is USDG, which converts into your USDC cash balance automatically. That is the part that matters for it to arrive correctly.
If you do not already have USDC, you can buy it on a crypto exchange that operates in your country and then send it to your fomo deposit address.