Cannot use multiple promo and advantage cards

Hoping someone at Dell can help me.  I have 6 Dell gift cards that I'd like to use on a purchase of a laptop.  Some are promo, some are advantage cards from purchases I've made this fall.  However, when I try to order, I'm told I can only use 2 gift cards plus a credit card for remaining balance.   I was instructed to call in and have the gift cards combined for use. However, the agent I finally reached in gift cards told me neither promo nor advantage cards could be combined.  This doesn't seem to match what I see on the terms site seems to say I could use up to 5 cards.  "Limit of 5 Promo Cards per order and per promotional offer for PC sales and limit of 10 Promo Cards per order and per promotional offer for electronic & accessory sales. Excludes Dell Advantage rewards".  Can someone tell me how I may use at least 5 of my gift cards?  I'd like to use them on a sale laptop before it goes off sale?  Many thanks.