<human>: Hey all!

I recently got a new job offer and I accepted. I'm really excited to get started, but my start date is about a month away. I did all the paperwork, filled out my info, and needed one thing changed. Contact was going really well and now it's been dead. 
It's been over a week with no response from my contact on their end. What should I do? I sent a follow up email 5 days ago, and left a voicemail yesterday. Should I send another email? Should I attempt to contact someone else? 
The no contact thing is making me a bit anxious, even though I have the offer letter signed and all... especially because I turned down other employment opportunities and put in my notice.
I guess maybe it's not a huge deal being that there's still 4 weeks till my start date?

Can you give me the gist of the text in a nutshell?
<bot>: I got a new job offer, signed the offer letter, started the onboarding process, now haven't heard from new employer in a week. Not sure what to do.