You can't get ahold of onsite HR via the phone you can only call the ERC for HR support. Anything else you have to go into the building to talk to her rep in person.
There's the chat bot thing on A to Z but it's not particularly helpful... I'm still pretty new there so I'm still trying to figure things out myself. I hate how hard it is to actually get human answers to anything.
Thanks! Your answer is awaiting moderation.