They are selling defect products and they do not care

Here most recent and probably last experience with MM Altona: I live next to it so in the last years I have been purchasing many products in it, at around 5000€. Last product I bought is "bose quietcomfort 35 series" a wireless headset. After having buy it, I realized there is a sound lag, when you watch YouTube or Netflix, the image and sound are not in synchronization. I then Googled the issue and it is apparently a well know problem since 2018. I live in a small apartment, so I do not like to have much stuff around, I normally throw away to reciclr all packages cartons. But I keep the invoice. The headset was in perfect condition as it was only couple days old, and barely used. So I went to give it back. I will not elaborate on the two ladies on the returns front desk, it was just terrible. Then I met the person in charge of the headset section. I explained what the problem was, his answer was "I will need to charge you 30€ for the missing box" that made me very mad because he basically, did not care about none of the words I said, he said "I need to sale that back and without a box I can't". Here the my the lesson I learned about MM Altona. They are just greedy and unfriendly they do not care about their clients, I told him to please check my profile on the computer so that he would see that I have expended quite a bit of money in that center, he did not care at all. I told him that to me the problem was not the 30€ euros he was asking for the missing box, the problem was that I was reporting to the that not that specific heatset but the model itself was defect ( you can Google it in many pages here a YouTube blogger talking about it https://youtu.be/8ddpj7uA1XU ) and that they should sent all the models back to Bose. He did not care at all. Currently that model is being promoted as a sale in on of the most visible stands, that makes me think they know about the issue and they just not care. And if they don't, shouldn't they be professional enough to know their roducts? At least listen to their clients?. They are basically sailing defects products to their clients, I told them, a d they do not care. To me that is simply cheap short sighted sales strategy, what a bunch of pirates. I left the headphones there to show him, that it is really not about the 30€. The cost of it was above 200€, I will never buy there again. I will know copy paste this in all the relevant blogs that might be relate to media Mark, so that people know. I will also send it to central media Mark support ( if anything like that) just to see if they care.