That is unbelievably callous - refusing to fix a known design fault when their own initial repairs fail.
The last time I spoke to VWCS I mentioned that, apart from worrying if I'll ever get a repair at all, my other big concern is that my 6 year warranty will be largely used up by the time any repair is done and the new quick-fix repair only carries a 12 month warranty. Given I could probably get a repair with Halfords rattle cans to last for 12 months it left me very concerned.
The advisor assured me that if the fix were found to be failing in the future that VW would not leave us in the lurch but would investigate and act appropriately. I asked for this to be put into writing - that if the repair later failed that VW would fix it, but was told that they wouldn't put that in writing.
Your experience (and others on this forum) suggest that VW are just playing for time until they can spin us off the end of the warranty with some half-baked coverup What on earth has happened to VW? I used to be such a big fan - they had everything - top quality, fantastic designs, great customer service - the lot.