I am sorry that you feel that things are not done, but actually they are.
An RMA is a quite long tedious, and not to say expensive process.
Your interface was not simply sitting at the distributor. They first need to double check that it is in fact defective before requesting the RMA, and then they contact us.
Once they do, we send them further instructions or ask them more questions so that we are completely sure it is defective.
There isn´t a repair center in the UK, so it has to be sent to Germany (Through customs etc…) then Audio service diagnosis it, repairs it, then it has to be billed, authorize and so on.
So while you think that the interface is just sitting there, some other things are happening in the background that might take a couple of days.
I personally issued your RMA Yesterday (Wednesday) at 11:27 am central European time.
I do not know at what time you brought it to the store on Monday… but it seems to be less than 48 hours which is a quite reasonable support time for this situation.
We always do our best to fix this kind of issues as soon as possible.
Thank you for your understanding!