My car is from 2016 and the Audi navigation maps were the original 2016 version. I logged in to MyAudi on my iPhone (use the website, not the app) and the site said I have used up my quota already of three free map updates but I could re-download the latest version that I was entitled to, which was 2019. I thought I’d do that today so I logged in on my PC and all browsers I tried said that there was no update available for my vehicle. Strange.....so I went back to my iPhone and downloaded all 14Gb of map data and transferred to my PC via my iTunes, and then loaded it onto an SD Card. It was a bit of a faff but I put it into my car and performed the update which worked perfectly. It took about 30mins or so to do install the new maps.
Perhaps you could try the same? Maybe you can get at least the 2018 version. Beats paying £250 anyway. I guess Audi have gotten wise to people sharing discs or buying copies from dodgy websites. They now make it very hard to get map updates for little money.