Zalando complaint: Not refunding returned items

After years of being a loyal customer, I started to get issues with Zalando returns this year. It has happened three times by now, that they claim they have not received the items I have 100% included in the returned parcels. Even took photos and videos of me packing the parcels, showing all items are included, and dropping it off at the service point. After having contacted them and sending them the declaration form (more than once, since they do not respond for weeks) they just simply decide not to refund several items due to “missing products”. They just do not take any responsibility in any of this, and all the missing items and money will go at the expense of the customer. Even if you have proof of including all items and dropping it off at the transport company THEY signed with, they do not care and will not refund your money. There is a total of over 700 euros they refuse to refund to me. It’s madness! Would not trust this company ever again after this.