Hmmm, have you tried cleaning your cookies and scanning for virus or malware? I just placed an order an hour or so ago, and all was fine. Even with me clicking all around, adding and subtracting to cart, etc..
Here are some links for the computer, if you can't download anything you may have a virus.
Cleaning: This is free:
CCleaner - Optimization and Cleaning - Free Download
Malware: Pick the free one:
Malwarebytes : Malwarebytes Anti-Malware PRO removes malware including viruses, spyware, worms and trojans, plus it protects your computer
Also, update your antivirus program and database, run a full scan.
Also might help to turn off computer, and unplug it and the modem for about 15 to 20 minutes.
Hope this helps. Otherwise you may want to call MadVapes and see if you can reach them, may be a glitch with software and your address, but that is long shot.
Here is the info:
7340 Smith Corners Blvd, Charlotte, NC 28269
Open Mon-Sat 10am to 7pm, Sunday 12pm to 5pm
Retail Store : (704) 597-1581
For Internet Orders or Support: (704) 624-8551