Bash app is disgusting and so not reliable

I ordered some stuff that was on promotion buy one get one free on Monday the 27th Nov 2023 and everything was processed just fine I even got a confirmation email, but to by surprise a day later another email came through saying they’re sorry the items I ordered were out of stock. Went back to Bash app where I place my order and guess what those items were listed there but with a normal price. And on Facebook everyone was talking about how their orders were cancelled due to the very same reason but on the app they were still available for the normal price too. Bash is so not reliable how do they advertise something on promo and then when everyone orders they cancel their orders