Had my GTD in for warranty replacement of a top mount, strangely similar experience to yours.
Got there on my lunch break as arranged, no sign of my original booking, had to suggest they look it up a different way, eventually found it, no loan car ready, gave me a brand new passat which was filthy, full of rubbish, empty water bottles and no diesel in the tank. Staff had obviously been using it. Had to stop the mechanic from getting into my car with no seat cover. What should have been a 10 minute in/out was 40 mins of nonsense and an unprofessional farce. Absolutely disgraceful.
Tore them to shreds when i picked my car up and on their feedback online survey and was contacted by them to offer an apology etc. They asked if I could come in for a chat, refused and told them I'd never be back. Got the VW Ireland feedback email a few days later and destroyed the dealer on that too. Haven't heard back from VWI.
Not really a surprise.