If you are afraid of interrupting them, then call them to see if they are busy and if they aren't then hang up and then call them.
Don't wait until the weekend. What is going to change between now and then other than they may get another offer?
If you are calling between noon and 8:00 at night then it is THEIR option not to answer the phone. I once had a band email me that they wanted me back for a second audition. For some reason it went into my junk mail. If I hadn't been proactive and
called them, they would have assumed that I wasn't interested. I've been with them over 2 years now.
As others have said, pick up the %#^$ phone and call ... now!