You'll need to contact tech support for an rma. Not a lot else to do. If it won't scratch start an arc, then it's like a larger issue. IF air isn't flowing it could be a torch switch though or the connector.

If you exceed 90 psi supply, yes you will make the regulator hiss. You MAY be able to tighten up the screws that hold it together, but beyond that, you may have blown out the seals or the gasket.