InPost mislabelled on collection

Encarta49

Please can anyone help? I sent a parcel, that I had sold via Vinted, to a customer. It was placed in the locker as instructed but it appears they mislabelled it and attached my label to someone else's parcel so my customer, didn't receive the items I had sent. The parcel she received also had another label and she was able to identify the correct recipient and duly sent it on. 
My problem is my parcel is now technically missing but inpost have it registered as delivered. I have sent numerous emails to inpost with just the automatic reply being sent. I even contacted Yodell (as the label my customer receive bore their name) and they can't help as none of the details on the label printed include my name or my customers name against the account details that link with their parcel number. They can't help due to data protection. I am now £15 down for the price of my goods and postage and no way of getting help. I have even tried my local Facebook groups to see if they have experienced a similar problem to try and solve the mystery. 
I cannot find any means of logging lost property, of talking to a customer service assistant or getting compensation.
Help please.

soolin

There are numerous threads on Vinted about this, it might be worth tagging o to one of them to see if anyone can suggest anything. 

There seems to be a real problem with items left for labelling, to the extent that I have followed the suggestions and now always opt to print a label, or else I print the scan code and stick that to the parcel so there is no mixing mine up with someone else’s parcel. 

The system appears to have broken down where Vinted are concerned. 

ticaha

This mislabelling problem has become so widespread that there are two Facebook groups set up to help reunite people with their items - search for Inpost Lost and Found parcels on there and they should come up. Once you've joined, check through the group photos and, if it's not there, post a screenshot of the order explaining that the wrong item received has been reunited with its real owner. It's not just vinted customers who've been affected (although since Inpost comes up so prominently as a delivery option, their users have been more affected than others), there've been parcels from ebay, asos, PLT, online returns and various others I can't remember, with the common factor being Inpost's lockers. From what we've worked out, Inpost's system relies on using their own internal code number which doesn't match the tracking numbers users get. This means they stick extra labels on at various parts of their process and the problem when these mislabelling incidents happen seems to be their software mixes up which internal code number should go with which tracking number and prints the wrong label which then gets stuck over the other label. Unfortunately, this means that, even if you print a label or stick other identifying factors on the parcel, they usually get ignored - the best thing to do in future is pop a note in with an email address asking to be contacted if the parcel doesn't reach it's intended owner. We think Inpost contract Citysprint to do collections from and deliveries to lockers, while home deliveries are passed on from Citysprint to Yodel for them to fulfil, with Inpost's software co-ordinating. Hope that makes sense.