Urgent advice needed. Transfer box failed after clutch replacement. B7 alltrack 2013

[juice]

Here’s the story.
My clutch started slipping. I took the car to a specialist gearbox firm who renewed the clutch and flywheel plus some extra work to the gearbox which he reported was damaged.
I got the car back and 3000 miles later the car goes bang. I’ve taken it back to the gearbox specialist and he tells me the transfer box has gone and I will need a new one.
my questions are,
Could this be related to the clutch repair?
Wheres the best place to source a replacement that’s not going to cost more than the cars worth?

Is a 2013 B7 alltrack manual.
any advices very welcome.

[Crasher]

I wonder if they set the oil level correctly? Too late to find out now. I get the replacement part number as being 0AV 409 053 AE which retails at £2008.13, otherwise you will have to hunt around for a used one, it will have a three digit code pushed into the surface which should be LPR, MKH, NFV and KRN, LNM, KZV (Golf R32) and I THINK these are all interchangeable. This unit was used right across the VAG range from 2004 to 2018 including models such as the S3. Personally I have never seen one fail, makes me very suspicious, I would like to see the unit stripped down.

[juice]

Thanks crasher. I’ve now been down and had a look for myself. There’s was oil in the transfer box. The mechanic said they had done it all properly but some damage might have happen with the original failure or its a coincidence. He has offered to do it heavily discounted. He will look first at a repair which judging by the noise won’t be possible then maybe a second hand one for around £400/450 or worse case a new one which I’ve seen discounted to around £1450. Then I need to think should I hang on to the car which I was intending to sell in the spring anyway. What annoys me is I’ve had it from new and there’s not a scratch on it, I've even had it serviced every 10k to look after it. Grr
Thanks again