Angry Customer

I'm very angry, I bought underwear on the 02/08/2020 on the online site. I went to pick it up and realised that the panties are not the same size, on the label it showed the same, but when you but them together the one is bigger than the rest. I think there was 2 that was out. I then took it back to the store where I went to fetch them. They said they'll have to send it in to their quality control department. We're are going for 3 weeks of me waiting for a response. This after I had to order online for those underwear since we never have stock for that size here in Heidelberg. I find this to be VERY unacceptable and what makes this even more unprofessional is that I have to wait so long for the underwear. Can someone please step in.