I have nearly always sorted my own brake issues as i was taught to do when i was in my late teens, i am now 65. However i have found out that Audi/VW brakes are a bit tricky to bleed, but still manage it. Last year i put a new rear axle on my Audi a3, and replaced everything on that new axle, suspension, wheel hubs. brake pipes. I only replaced the brake calipers a few years ago, so reused them. I find bleeding is not easy on Audi's and VW's, and have encountered the same issues on the odd occasion the garage has worked on them. The brake pedal can be very spongy. But after driving it for a few days, it corrects itself. At worst, it took nearly two weeks, that was after last years rear axle change. I suggest drive very careful for a week or two, and it should correct itself.