If you are wanting to purchase additional phones or accessories through the SpectrumVoIP Store, you can do so at www.spectrumvoipstore.com
If you are a Tax Exempt organization, you are able to take advantage of your status when making a purchase.
To do so, simply check out like normal, then when you get to the payment information section you will see a "Send Additional Instructions" field.
Click on the check box.
Enter in "TAX FREE" (all caps with a space between the words)
Continue with your payment like normal.