Well yes and no. They're both at fault.
Thomann are using DHL's bottom tier of services for returns, for you to become a DHL UK Parcels vendor you need a click to pay card system installed in your premises that's it, you then scan the parcel, an email is then sent to DHL to come and pick the parcel up, you pop a sticker on the parcel box... you get 20p if and when DHL turn up.
Now if you're DHL you're not going to drop everything and go and pick up 1 parcel, so you're bottom of the queue, forever it seems, when I went back to the shop to collect my parcel they showed me the room where they keep all the return parcels dropped off with them and there were hundreds, no word of lie, hundreds, no one from DHL had been there for weeks. Imagine DHL's system, I doubt they have a record of all 3500 return points and how many parcels each one has... and how long until the emails telling them to come and get the parcels are archived and forgotten about.
Now this is when I think it is Thomanns responsibility to do more, I spent £500, got a shoddy product, I want that money back, Thomann want their stock back, Thomann are happy to wait an indefinite amount of time to have the parcel picked up at one of these DHL Parcel UK points, even when it is picked up, it then goes to a UK Thomann HUB and then forwarded back to Germany, they state at the hub "please expect up to 3 weeks for the parcel to leave and arrive in Germany", so at this point with doing the absolute bare minimum they're happy to wait possibly 8 weeks to get the bass back and only then issue a refund... I'm without a bass and the funds to buy a bass for 8 weeks, all for their inability to QC an outgoing product properly.
After kicking off and refusing another DHL Parcels UK label (what on earth was that going to achieve) full fat proper DHL are coming to me this Wednesday... it's still possibly going to sit at the UK hub for 3 weeks mind...
I'm going to stick to UK vendors moving forward, such a shame as I always had good things to say about them!