If an online company is hacked, it is often due to negligence on the part of the company. If you have a good lawyer and can prove that, you may have a case.

Many companies with online operations these days are excessively careless. They like to claim that they have no control over hacking, but that is almost never true. If more people sued, it would make such carelessness a lot more expensive, and companies would learn to be more careful. You have to make security less expensive than insecurity by forcing companies to pay dearly when they are careless, and only then will they learn to behave.