Too clunky, bigger than expected. It doesn't lie well on my dog's neck.

I bought this collar in medium size in December 2022. Although I was not very happy at the way the collar sits on my dog's neck (very stiff), I thought the material would eventually soften somewhat and it would be fine. I do like the reflective stitching which is very effective. However, my dog has been able to open the closure on the collar at least 5 times and get away from me. All she did to accomplish this was simply pull away to chase another animal, or resist me tugging her to change direction. Each time the collar simply opened right up! This happened even after I have confirmed that the closure is securely closed each time we leave the house. Because I'm so nervous to use this collar, I've ordered a new collar for her from a different brand and will dispose of this one. Not sure if this is just the way my dog wears the collar or is there really an issue with this specific collar. I'm just not taking any more chances with it.