Not enough support around the ankle

So I looked at the sizing guide measured my feet and based on the recommendations from others to size up to a 7 (I wear 6.5 in my street shoes) this is also my first pair of hella heels so maybe I should’ve gone with a size 6. I do like that the toe opening is narrow that it doesn’t give me cliffhanger toes like pleasers do, but I do feel like my heel is about to slide out of the shoe an any moment. Especially when pointing my feet. The ankle strap feels really loose even at the tightest setting. And I feel like the two straps that connect the ankle strap to the shoe are a little too long so it doesn’t help securing the shoe to the heel of my foot. I wish there was a way to adjust them for a better fit. I’m a little disappointed that I will most likely need to make alterations to them in order to wear them comfortably and with confidence. The shoe itself is beautiful! I love the color and the quality feels great. I am in the US and ordered these from the Australia site because of how much I loved them, but with the cost of shipping and the amount of time it took to receive them, I didn’t think it was worth returning them.