Bests & Worsts Reviews from Amazon

I had just bought a house so I applied for this card to buy some office furniture among other things on promotional financing. Pretty straightforward, as I've used promo financing many times in the past. Also as a Prime member, I use Amazon for a lot of purchases including Subscribe and Save items, so I use the card often. I was surprised however a few months ago to see my first finance charge on the card. Went in to the statement to find that somehow my promotional balances were paid off months before the promotion was to expire, and all I had left was interest accruing balances. I thought hmm, maybe I have something set wrong... went into the settings online, and made sure the option to pay off interest accruing debt first was checked, and moved on. I continued using the card... got a couple more promotional financing items. Continued to responsibly use the card and make payments on time/pay all interest accruing amounts, etc. Just got hit with another finance charge - lo and behold, my interest-free balances are paid off months early, as all of the hundreds of dollars of payments I've made went to those purchases instead of the ones that are accruing interest. I don't have the time or energy to figure out why this doesn't work like any other card I've used, so I will be paying it off and never using it again.