Dress torn during the people

Generally I like woolworths, sells quality stuff including their food. However the embarrassing moment I had yesterday at a doctor's suit... Realizing my bums are out. I wanted to go ask the Doc, the receptionist, the patients, etc... The cleaners in passages.. if they saw anything.

So I bought this edition dress 2019 just after winter.... It's generally a loose dress so I honestly don't understand whi it just opened on the bums. Or whether it's the material. I haven't recovered from that trauma.. My husband had to go buy pins, I couldn't leave the doctor's suite knowing my bums are out. Yes it's not a new dress, but i have probably worn it 4 or 5 times.. It was the first time this year nogaal. Last year I never worn it. Probably last worn at work before covid few times. Even if one can go through my phone, you will only find one pic.. I rarely wore it, soo this is surprising. If this had an attachment option to show this pic right now.