Under promise over deliver

Honestly the most efficient and fast online clothing site I’ve ever used, they use the notion over “Under promise and over deliver” which honestly in my view is very effective. I just did not appreciate the fact that they had canceled my delivery for a later day only to deliver on the initial day they had said they would deliver, and they delivered without notifying me before arrival. Luckily I was at the house to receive the package. Other than that I would’ve easily given them 5 stars.