[Brekkie]

I think if you've subscribed directly to Prime Vidro you have an argument, although suspect the T&Cs probably cover the eventuality. It was annoying when NOW did similar a few years back but in reality it's usually a minute of ads at the beginning then 30 seconds for the breaks.

If you get it via Prime though I think it's spun as a free add on so probably more of a grey area. However my membership just says "Unlimited streaming of Amazon Originals, movies, TV shows, and live sports" without saying they are ad free.