how long?For Billing question to get answered?

how long does it take for an enquiry to be responded to typically? it's been almost 2 days since I sent an enquiry and I have no response?

I need to add my sister's name to the bills, but I don't see the option to do so on the website. I already added them on my account and have made them a manager. What I want in simple terms is for the name to  show on the billing statement.  So:

Mr A

Mrs B

P sherman Way,

000000, baltimore,

MD

I read somewhere that employees may be able to do that from their end, is that still true? Who can I message? otherwise, how can I sort this out very fast?  I am in Maryland.

Thanks