I guess they can't selectively decide which part of the contract to treat as invalid. They will have rights against the club for non-payment but unless they end the whole contract the club will still be able to enforce the terms. So they can talk away but risk their jobs if/when it's sorted.
Hardy now has a track record of saying things that don't come to pass. It may not be a lie when he says it but they don't end up being truths either.
Curtis as a journalist should absolutely harangue Hardy, especially now that he's chickened out of speaking to him and now speaks to another publication that is more compliant, basically an uncritical dictaphone of a newspaper.
Until the contract is signed every utterance of Hardy should be taken with an ocean of salt.