The following is from their rules:
Your receipt of an electronic or other form of order confirmation does not signify our acceptance of your order, nor does it constitute confirmation of our offer to sell. MLC Distribution reserves the right at any time after receipt of your order to accept or decline your order for any reason. MLC Distribution reserves the right at any time after receipt of your order, without prior notice to you, to supply less than the quantity you ordered of any item. We may require additional verifications or information before accepting any order of any amount.