Screwed by Bundled Shipping!

I sold 5 items in a bundle, each item was 1 oz label, except one was supposed to be Priority Mail 3 oz. So that's 7 ounces all together. When I printed out the now $12 shipping Ground Advantage label, it's for 2 f@#$ing pounds. Makes no sense, just wasted more of my money. pardon my outburst.