You can (1) obtain an invoice from the vendor and request a check from SACBO. (This must be done at least 3-4 weeks prior to the time you actually need the items if the vendor wants the check before shipping), (2) ask the vendor if they will accept a purchase order, or (3) pay for the goods with a personal credit card.
Whichever option you choose, you will need to submit an invoice from the vendor in order for SABCOto process the check request. If paying by credit card, please submit a copy of your credit card bill as well. Remember that you cannot be reimbursed for tax.