I'm confused about why you think that maxing out your card and dropping your utilization ratio on this card is going to impress US Bank?
It sounds like the fraud department is doing their job to me. Just use the card as your daily spending card if you want to impress them instead of coming up with elaborate schemes to charge thousands of dollars through your $4k limit card in one month.
+1 to the money laundering and fraud. I have also read that you will NOT always earn points on gift cards and cash advances, cash back, the form checks they send you to use as a cash advance, etc. Far better to purchase/use the card for real living expenses. What you have attempted has been tried too many times before. It does raise way too many flags and no, you do not have grounds for a complaint. The Card Issuer has control over APPROVED TRANSACTIONS. What they are trying to tell you is they do not like what you are attempting to accomplish.