It's awful to hear people are still waiting on their DVDs, we got married May 2014 & finally got the DVD March 2016 after a lot of hassle. The quality isn't great at all, really not worth the money we paid for it, but at least it's better than nothing. From what I know, I don't think they are at their address in Naas anymore (although that may have changed since I was trying tot track them a year ago), so going down the legal route is difficult.
There was a feature on this on the Anton Savage show on Today FM last year - they initially didn't name D Digital, but did later on in the show as so many people had been in contact with the station with the same issues. Might be worth contacting the station, or even other media outlets- if enough people are telling the same story someone might run with it again.
Good luck everyone, hope you all get something soon.