How long does it take for Oracle to roll out an offer letter?

Reposting this question once again as I am on a time-crunch.

I completed my interviews last week in April and submitted my data for the background verification process on May 14th. Apparently, the background verification was completed last week, which I was completely unaware of, but there’s radio silence from HR. I emailed her twice (today I emailed her asking for a definite update by mentioning a time-sensitive decision that I have to make), and called her (she didn’t pick up the call). So, is my offer gone? And the HR is now ghosting me about it?

This is my first time trying to switch companies and I have no experience on what the timelines and processes are going to take place. So, please give me any sort of insights that are applicable here.