Blockchain is just a piece of information stored in a decentralized manner on many computers all over the world. It doesn't have customer support. If your transaction is stuck due to low fees and mempool congestions, you usually want to speed it up with technologies like CPFP or RBF, but if it is impossible to employ these techniques, then you just wait until your transaction gets removed automatically from the pool of unconfirmed transactions. It usually takes no more than two weeks from the moment you first broadcast your transaction. These rules apply to all wallets where you fully control the private keys to your coins, where you can set custom fees or "withdraw" funds at any time. If third parties control the private keys to your wallet, you have less or no power whatsoever. You instead always rely on these third parties' honesty and trust them that they will not deceive you while making financial transactions. Sometimes they fail even at simple tasks such as setting correct fees.